The infrastructure of the Web 2.0 is complex and changing in nature, but it always includes:
- server software,
- content syndication,
- messaging protocols,
- navigation standards
- various client applications (plug-ins, or grafts, non-standards are generally avoided).
These complementary approaches provide Web 2.0 storage capacities, creation and dissemination, as well as much higher than what was previously expected websites serendipity.
A site could be considered as part of a Web 2.0 approach if uses in a special way the following techniques:
- CSS, XHTML markup semantically valid and microformats;
- technology-rich applications such as Ajax;
- RSS / Atom syndication and aggregation of content;
- categorization labeling;
- appropriate use of the URL;
- REST or XML web services.
Web 2.0 is defined by its content, the shift to Web 2.0 therefore has nothing to do with the evolution of communication standards such as the transition to IPv6.
Rich Internet Application
Since the turn of the century, the rich Internet application techniques such as AJAX have improved the user experience of applications using a web browser. A web application using AJAX can exchange information between the client and the server to update the contents of a web page without refreshing the entire page using the browser. The “Geospatial Web” is one of the emerging forms of geographic recomposition of the entries of knowledge through ICTs, democratization of GPS and sometimes crowdsourcing applied to the citizen mapping, who gave OpenStreetMap for ex., and in other scales the NASA World Wind, and Google Earth, and Microsoft Live Local in 3D with environmental, social and economic still poorly understood impacts.
The first important move towards Web 2.0 was content syndication, using standardized protocols that allow users to make use of data from one site in another context, from another website to a browser plugin , or even a separate desktop application. These protocols include RSS, RDF (as in RSS 1.1) and Atom. All are based on XML. Specialized protocols such as FOAF and XFN (both for social networking) extend the functionality of the site and allow users to interact in a decentralized manner.
This bottom-up trend that many of these protocols become de facto standards rather than standards.
Tags or labels or keywords improve semantic search, more heuristic and therefore presented in the form of a tag cloud.
These labels are small text expressions that describe a concept, are attached to a concept and used for searching content (typical examples: a forum, a blog, a blog directory) and, more importantly, interconnect things together. A bit like a neural network: the more a label is used, the more the concept attached to the label is present and it takes more weight. More labels are present and more the attached concepts are interconnected.
The “markers” can include meta-elements (ie metadata).
Social tagging, folksonomy
The label provides a hierarchical prior sorting of sought items. The order of items is either the number of references or a “satisfaction rating” given by readers. In the latter case, the weighting scheme is defined by a human factor (the social side) which highlights some interesting data or articles in the mass of information. This is typically the case of social bookmarking.
Web communication protocols are a key component of the Web 2.0 infrastructure. Two main approaches are:
- REST (REpresentational State Transfer) indicates a way to exchange and manipulate data by simply using the HTTP GET, POST, PUT and DELETE verbs.
- SOAP, which involves posting to a server XML queries with a set of instructions to be executed.
In both cases, access to the services are defined by an application programming interface (API). Often, the interface is specific to the server. However, standardized interfaces to web programming (for example, to post on a blog) emerge. Most, but not all, communication with web services involve a transaction as XML (eXtensible Markup Language).
There is also WSDL (Web Services Description Language), a standard for the publication of Web Services interfaces.
After the gains due to the new economy, Web 2.0 has enabled the rapid enrichment of a few companies, as was the case during the first broadcast of the Web. And Facebook founder Mark Zuckerberg became a billionaire at age 23.
However, some were worried about the risk of developing a “2.0 bubble” similar to the first internet bubble. The blog TechCrunch, first blog of the A list, even made an article announcing the death of Web 2.0, the headstone marked “2004-2008” (which is also a valuable reference in the difficult task of dating the birth of the Web 2.0). But contrary to what was held for the first Internet bubble, this time the internet activities are not behind the 2008 crisis.