Web 3.0

What is next after Web 2.0?  It's got to be Web 3.0 but what is it?  Officially it is Semantic Web.  The semantic web is relatively unknown to most people and some of the technologies are very complex to understand.
Technologies or formats such as FOAFAPMLSIOCXFN tags and microformats are some of the building blocks of the social aspects of the semantic web. They are used to create cross-site profiles of people and also represent relationships between them. XFN and microformats are somewhat easy to start using, but FOAF, APML and SIOC are a different story.
As time goes on I will try to explain each format and how it can be implemented.