Semantic search via forum software search engines has always been a challenge - the challenge being the brute processing power required to maintain and update the index; as Adam mentioned; a full crawl taking 10 hours.

This, combined with the site having to protect against a denial-of-service attack using search queries, makes things simpler if you at least have an idea of the forum in which to search within the site, and then limit your search that way.

Either that, or help DCG find a way to fund a server / search architecture that permits for 5 minute incremental search engine updates without detracting from the overall site performance. A dedicated search / index server farm would be a solution - but at what cost ?

Personally, I've never had issues with the search here on DNF - but I do run my searches with keywords and refinements knowing that it will help in getting to the content I need...

Just my $0.02 (as someone who works in IT architecture and with community software systems )

Rob