Semantic web is considered the next big thing on the internet and its also called Web 3.0. Its an extension of the WWW where the web content can be expressed not only in natural language but also in formats that can be read and understood by machines. This will allow better search crawls and organization of information.

Tagging which is an essential part of web 2.0 can be considered as a light weight form of Web 3.0 Tags allows a broad classification of data, and these tags are machine readable also. The  number of <em> </em>  tags around a keyword emphazies on the importance of that keyword according a parameter that is set by the programmer.