What is Web 2.0? According to Wikipedia:

... the phrase "Web 2.0" hints at an improved form of the World Wide Web; and advocates suggest that technologies such as weblogs, social bookmarking, wikis, podcasts, RSS feeds (and other forms of many-to-many publishing), social software, Web APIs, Web standards and online Web services imply a significant change in web usage.

A Web 2.0 website may typically feature a number of the following techniques:

• Rich Internet application techniques, optionally Ajax-based
  
• CSS
  
• Semantically valid XHTML markup and the use of Microformats
  
• Syndication and aggregation of data in RSS/Atom
  
• Clean and meaningful URLs
  
• Extensive use of folksonomies (in the form of tags or tagclouds, for example)
  
• Use of wiki software either completely or partially (where partial use may grow to become the complete platform for the site)
  
• Weblog publishing
  
• Mashups
  
• REST or XML Webservice APIs

Welcome to a new stage of evolution. We're getting more connected, whether you're ready or not.

Technorati: web 2.0, css, xhtml, social networking, folksonomies, xml, ajax