George Hubka

essentially using the results of the first search to expand to find more revelant results

It works by performing the search twice, where the search phrase for the second search is the original search phrase concatenated with the few most highly relevant documents from the first search. Thus, if one of these documents contains the word “databases” and the word “MySQL”, the second search finds the documents that contain the word “MySQL” even if they do not contain the word “database”. The following example shows this difference:

http://dev.mysql.com/doc/refman/5.0/en/fulltext-query-expansion.html