There there are plenty of user defined functions posted on the web that will parse a string into a resultset of keywords, compare two strings, etc. They may provide the functionality you're looking for, but understand that parsing keywords from varchar or text based columns tends to perform very poorly, because it leverages looping constructs and is not indexable.
However, perhaps you were reading an article on SQL Server 2012's new Semantic Search service.
... provides deep insight into unstructured documents stored in SQL Server databases by extracting and indexing statistically relevant key phrases. Then it also uses these key phrases to identify and index documents that are similar or related ...
http://msdn.microsoft.com/en-us/library/gg492075.aspx
If you don't have SQL Server 2012, then look into the Full-Text Search service, which is robust and has been around for decades in several past releases of SQL Server.
http://msdn.microsoft.com/en-us/library/ms142571%28v=sql.105%29.aspx
"Do not seek to follow in the footsteps of the wise. Instead, seek what they sought." - Matsuo Basho