La Web 2.0 es la representación de la evolución (la transición) de las aplicaciones tradicionales que funcionan a través de la web enfocadas al usuario final. La Web 2.0 es una actitud con la que debemos trabajar para desarrollar en Internet y no precisamente una tecnología.Antes, la web se era un entorno estático, con páginas en HTML que sufrían pocas actualizaciones y no tenían interacción con el usuario. Ahora se emplean aplicaciones que generan colaboración, y servicios que reemplacen las aplicaciones de escritorio.

Todo inició cuando Dale Dougherty utilizó este término en una conferencia en la que compartió una lluvia de ideas junto a Craig Cline en la que hablaba del renacimiento y evolución de la web.

Constantemente estaban surgiendo nuevas aplicaciones y sitios con sorprendentes funcionalidades. Así se dio la pauta para la Web 2.0 conference de 2004. Esta conferencia no solo fue exitosa sino que ya tuvo seguimiento en la Web 2.0 Conference del 2005 celebrada en Octubre.

En la charla inicial del Web Conference se habló de los principios que tenían las aplicaciones Web 2.0:

• La web es la plataforma.
• La información es el procesador.
• Efectos de la red movidos por una arquitectura de participación.
• La innovación surge de características distribuidas por desarrolladores independientes.
• El fin del círculo de adopción de software (“Servicios en beta perpetuo”).

La Web 2.0 con ejemplos

La forma más fácil de comprender lo que significa la Web 2.0 es a través de ejemplos. Podemos comparar servicios web que marcan claramente la evolución hacia el Web 2.0:

• Web 1.0 > Web 2.0
• Doubleclick –> Google AdSense (Servicios Publicidad)
• Ofoto –> Flickr (Comunidades fotográficas)
• Akamai –> BitTorrent (Distribución de contenidos)
• mp3.com –> Napster (Descargas de música)
• Britannica Online –> Wikipedia (Enciclopedias)
• Sitios personales –> Blogs (Páginas personales)
• Especulación con dominios –> Optimización en motores de búsqueda
• Page views –> Cost per click
• Content Management SystemsPrevisualizar » –> Wikis (Manejo de contenidos)
• Categorías/Directorios (taxonomía) –> Tagging (“folksonomy”)

Tecnologías que dan vida a un proyecto Web 2.0:

• Transformar software de escritorio hacia la plataforma del web.
• Respeto a los estándares del XHTML.
• Separación de contenido del diseño con uso de hojas de estilo.
• Sindicación de contenidos.
• Ajax (Asincronical javascript and xml).
• Uso de Flash, Flex o Lazlo.
• Uso de Ruby on Rails para programar páginas dinámicas.
• Utilización de redes sociales al manejar usuarios y comunidades.
• Dar control total a los usuarios en el manejo de su información.
• Proveer APis o XML para que las aplicaciones puedan ser manipuladas por otros.
• Facilitar el posicionamiento con URL sencillos.

¿En qué nos sirve la Web 2.0?

El uso de el término de Web 2.0 está de moda, dándole mucho peso a una tendencia que ha estado presente desde hace algún tiempo. En Internet las especulaciones han sido causantes de grandes burbujas tecnológicas y han hecho fracasar a muchos proyectos.

Además, los proyectos tienen que renovarse y evolucionar: en Internet, el cambio debe de estar presente más frecuentemente.
        Conclusión personal: la Web 2.0 está siendo una de las aplicaciones que más está trascendiendo la sociedad actual. Las redes sociales están teniendo un impacto impresionante y de alguna manera están cambiando las actitudes y costumbres de la gente. A pesar de este cambio en el que todo parece moverse en torno a la Web, hay gente como Nieves González que cree que solo se trata de una moda pasajera: “La 2.0 es solo un término de moda que pasará como ya antes pasó con “Las superautopistas de la información”.
Sin embargo yo no creo que sea así, las necesidades o imposiciones por parte de la sociedad en cuanto al uso de Web, parece mucho más fuerte que una simple moda pasajera.

       Information taken from:

•  http://www.maestrosdelweb.com/editorial/web2/
• http://bibliotecarios2-0.blogspot.com/2007/05/bibliotecarios-20.html (Biblitecarios 2.o de Nieves González)
• To read further*: http://www.oreillynet.com/pub/a/oreilly/tim/news/2005/09/30/what-is-web-20.html?page=5

* Some important ideas taken from the last link:

• One of the key lessons of the Web 2.0 era is this Users add value. But only a small percentage of users will go to the trouble of adding value to your application via explicit means. Therefore, Web 2.0 companies set inclusive defaults for aggregating user data and building value as a side-effect of ordinary use of the application.
• The Web 2.0 lesson: leverage customer-self service and algorithmic data management to reach out to the entire web, to the edges and not just the center, to the long tail and not just the head.
• The Web As Platform: Like many important concepts, Web 2.0 doesn’t have a hard boundary, but rather, a gravitational core. You can visualize Web 2.0 as a set of principles and practices that tie together a veritable solar system of sites that demonstrate some or all of those principles, at a varying distance from that core.

INFORMATION TAKEN FROM:

http://www.webopedia.com/TERM/m/metadata.html

http://www.library.uq.edu.au/iad/ctmeta4.html

http://en.wikipedia.org/wiki/Metadata

Metadata is structured data which describes the characteristics of a resource. Metadata is data about data (An item of metadata is itself data and therefore may have its own metadata). It shares many similar characteristics to the cataloguing that takes place in libraries, museums and archives. Metadata is essential for understanding information stored in data warehouses and has become increasingly important in XML-based Web applications. David Marco, another metadata theorist, defines metadata as “all physical data and knowledge from inside and outside an organization, including information about the physical data, technical and business processes, rules and constraints of the data, and structures of the data used by a corporation.”

Metadata is data associated with objects which relieves their potential users of having full advance knowledge of their existence or characteristics.

The term “meta” derives from the Greek word denoting a nature of a higher order or more fundamental kind. A metadata record consists of a number of pre-defined elements representing specific attributes of a resource, and each element can have one or more values. Below is an example of a simple metadata record:

Each metadata schema will usually have the following characteristics:

• A limited number of elements
• The name of each element
• The meaning of each element

Typically, the semantics is descriptive of the contents, location, physical attributes, type and form. Key metadata elements of documents include the originator of a work, its title, when and where it was published and the subject areas it covers. The resource community may also define some logical grouping of the elements or leave it to the encoding scheme. For example, Dublin Core may provide the core to which extensions may be added. When structured into a hierarchical arrangement, metadata is more properly called an ontology or schema.

Some of the most popular metadata schemas include:

• Dublin Core
• AACR2 (Anglo-American Cataloging Rules)
• GILS (Government Information Locator Service)
• EAD (Encoded Archives Description)
• IMS (IMS Global Learning Consortium)
• AGLS (Australian Government Locator Service)

There are hundreds of metadata schemas to choose from, as different communities seek to meet the specific needs of their members. While the syntax is not strictly part of the metadata schema, the data will be unusable, unless the encoding scheme understands the semantics of the metadata schema. The encoding allows the metadata to be processed by a computer program. Important schemes include:

• HTML (Hyper-Text Markup Language)
• SGML (Standard Generalised Markup Language)
• XML (eXtensible Markup Language)
• RDF (Resource Description Framework)
• MARC (MAchine Readable Cataloging)
• MIME (Multipurpose Internet Mail Extensions)

Metadata may be deployed in a number of ways:

• In the Web page by the creator or their agent using META tags in the HTML coding of the page.
• As a separate HTML document linked to the resource it describes.
• In a database linked to the resource. The records may either have been directly created within the database or extracted from another source, such as Web pages.

The simplest method is for Web page creators to add the metadata as part of creating the page. Creating metadata directly in a database and linking it to the resource, is growing in popularity as an independent activity to the creation of the resources themselves. Increasingly, it is being created by an agent or third party, particularly to develop subject-based gateways.

Metadata has many different applications:

- It provides the essential link between the information creator and the information user.
-To improve resource discovery: to speed up and enrich searching for resources.
-To provide additional information to users of the data it describes. This information may be descriptive.
- It helps to bridge the semantic gap. By telling a computer how data items are related and how these relations can be evaluated automatically, it becomes possible to process even more complex filter and search operations.
-Certain metadata is designed to optimize lossy compression algorithms.
-Some metadata is intended to enable variable content presentation.
-Other can be used to automate workflows.
-Metadata has become important because of the need to find useful information from the mass of information available.

The metadata elements fall into three groups which roughly indicate the class or scope of information stored in them: (1) elements related mainly to the content of the resource, (2) elements related mainly to the resource when viewed as intellectual property, and (3) elements related mainly to the physical manifestation of the resource. See further in the page of Dublin Core (which has become the defacto Internet metadata standard) or the previous article

The <META> tag is not normally displayed by Web browsers, but can be viewed by selecting “Page Source”.

Which elements, sub-elements and schemes should be used?

The choice, it is normally based on:

• The specific needs of the local community to maximise information retrieval and management.
• The need to guard against making the creation of metadata and its maintenance more trouble than it is worth and therefore defeating its purpose.
• Sustainability of the metadata schema in terms of keeping the records up to date: It is not economical to start attaching metadata only after the production process has been completed.

The level of specificity in resource description is also important. The resources can be described individually or at a collection or aggregate level.

Consistent use of language with metadata descriptions can aid in the consistent discovery of resources.

Where will the metadata be stored?

-Metadata can be stored either internally, in the same file as the data, or externally, in a separate file.Metadata may be deployed in a number of ways:

• Embedding the metadata in the Web page by the creator or their agent using META tags in the HTML coding of the page
• As a separate HTML document linked to the resource it describes
• In a database linked to the resource. The records may either have been directly created within the database or extracted from another source, such as Web pages.

Creating metadata directly in a database and linking it to the resource, is growing in popularity as an independent activity to the creation of the resources themselves. Increasingly, it is being created by an agent or third party, particularly to develop subject-based gateways.

For metadata attached to Web pages, the standard encoding scheme is HTML (HyperText Markup Language). RDF (Resource Description Framework) supports multiple metadata schemes. It uses XML (EXtensible Markup Language) to express the structure.

How does one create metadata?

The more easily the metadata can be created and collected at point of creation of a resource or at point of publication, the more efficient the process and the more likely it is to take place. There are many such tools available and the number continues to grow. Some examples include:

• DC-dot – http://www.ukoln.ac.uk/metadata/dcdot/. This service will retrieve a Web page and automatically generate Dublin Core metadata, either as HTML tags or as RDF/XML, suitable for embedding in the section of the page.
• DCmeta – http://www.dstc.edu.au/RDU/MetaWeb/generic_tool.html. Developed by Tasmania Online. It is based on SuperNoteTab text-editor and can be customised.
• HotMeta – http://www.dstc.edu.au/Research/Projects/hotmeta/. A package of software, including metadata editor, repository and search engine.

Types of metadata

There are two distinct classes of metadata: structural or control metadata and guide metadata. Structural metadata is used to describe the structure of computer systems such as tables, columns and indexes. Guide metadata is used to help humans find specific items and is usually expressed as a set of keywords in a natural language.Metadata can be classified by:

• Content: Metadata can either describe the resource itself or the content of the resource.
• Mutability: Immutable or mutable (the “Scene description” does change).
• Logical function: There are three layers of logical function: subsymbolic layer, the symbolic layer and the logical one.

Digital library metadata

There are three categories of metadata that are frequently used to describe objects in a digital library [3][4]:

1. descriptive – Information describing the intellectual content of the object, finding aids or similar schemes. It is typically used for bibliographic purposes and for search and retrieval.
2. structural – Information that ties each object to others to make up logical units (e.g., information that relates individual images of pages from a book to the others that make up the book).
3. administrative – Information used to manage the object or control access to it. This may include information on how it was scanned, its storage format, copyright and licensing information, and information necessary for the long-term preservation of the digital objects.

In a nutshell, search engines, such as Google and HotBot, consist of a software package that crawls the Web, extracts and organises the data in a database. People can then submit a search query using a Web browser. The search engine locates the appropriate data in the database and displays it via the browser. This is not to be confused with directories such as Yahoo, that provide subject lists created by humans, that must be browsed. Search engines have three major elements:

• The spider: It visits a Web page, reads it, and then follows links to other pages within the site. The spider returns to the site on a regular basis, such as every month or two, to look for changes.
• The index. Everything the spider finds goes into the index. The index, is like a giant book containing a copy of every web page that the spider finds. If a web page changes, then this book is updated with new information.
• Search engine software. This is the program that sifts through the millions of pages recorded in the index to find matches to a search and rank them in order of what it believes is most relevant.

Search engine software is also available to run on a local Web site. The software has the same basic components, but the spider just visits the local site or a limited number of sites in a community.

Internet isn’t a search engine good enough

Because it popularisation in the mass media, the Web has become a two-edged sword. It is now very easy to publish information, but it is becoming more difficult to find relevant information. For outsiders and casual users, much of the useful material is difficult to locate and therefore is effectively unavailable.

The Working Group on Government Information Navigation outlined the problems with Internet search engines:

• relevant information can be missed because sites contain types of resource in addition to HTML text (e.g. images, databases, PDF documents);
• the search engines frequently do not harvest every page on a site, but often only the top two or three hierarchical levels, thus missing significant documents which, on larger and more complex sites, may be located in lower levels of the hierarchy;
• search engines, especially the more comprehensive ones, may index sites on an infrequent basis and may therefore not contain the most current data; and
• irrelevant information can be retrieved because the search engine has no means (or very few means) of distinguishing between important and incidental words in the document text.

The introduction of the <META> element as part of HTML coding, was in part, an attempt to encourage search engines to extract and index more structured data, such as description and keywords. However, search engines are rather proprietorial in recognising <META> tags. It ranges from no support at all, to reasonable. Details are available from Search Engine Watch [SEW].

Support for <META> tags by search engines designed for local Web servers varies from non-existent to good. Some of the specialist packages include support for Dublin Core or other metadata schemas.

Information taken from: http://www.webopedia.com/TERM/m/metadata.html

We have been dealing with many reference pages during our classes. Del.icio.us is a page where we can add our favourite links. I find it very useful, since in the explorer (either Firefox or Internet Explorer), although they already have an option where we can add a link to our favourite pages, if we add to many this option can become even disturbing. On the contrary, in del.icio.us, we have a right-column tags where we can divide our links into cathegories, in order to make our research easier. We can see those tags either in a cloud or in a list. The advantages of seeing them in a list is that the number of articles related to that theme is showed; while in the cloud, the most used tags are highlighted with a bigger size of letter, and they are showed in a smaller space. We can see an example of it in the account of Joseba Abaitua in del.icio.ous.

We have been also dealing with reference pages like Wiki. Some of the advantages of this page is the nice presentation it shows and the possibility to click on the links and go from one place to another (seeing different works, recent changes… ). But the most useful thing it offers is the possibility of comparing your own work, the evolution it has made, and the dates where those changes have been made (we can compare two versions of the same text saved on different dates, and see all the changes made -which appear in another colour-). Nevertheless, from my point of view, this page has a lot of dissadvantages: It takes a lot of time in making a nice presentation, putting internal and external links and fulfilling those pages in a proper way. Moreover, if you want to indent a paragraph, or put some words of the text in bold or in italics, you can’t see the changes in your text while you are writing, you just see two or three inverted commas, or asterisks surronding the words, which makes things no easy. You have to save what you are doing and see what you have done, make changes and see what you have done until you get the presentation you want. In comparison, Word programm is much more easy and fast, because you can see the presentation while you are writting. Moreover, with this wiki programm you have you save what you are doing constantly. If you spend a lot of time without saving your changes, it appears the page to login again, and you have lost all the work you have made (in many cases, clicking on the returning arrow, does not lead you to your previous work, which is fustrating). And the last dissadvantage of this page is, that as you can see other people’s work without any restrictions, many people can copy other people’s work and show it as his/her, just by introducing some little changesnd with no control.