Alternatives to Built-In MySQL FullText Search
Searching the communities might be a trivial task at the moment, but as our data grows, we'll require a more robust utility to handle the processing of many concurrent searches. I've been researching these tools, and I came across a pretty awesome discussion between several big players in the open-source searching "business".
Take a look:
http://www.mysqlperformanceblog.com/2006/06/26/full-text-search-for-all-mysql-storage-engines/