bbPress deviates from WordPress's search functionality just a bit, so it's worth making a dedicated issue for it here.

Thankfully, bbPress topics and replies are just post types, so it's easy enough to grok. Providing fast and reliable relevancy-based results in a forum dramatically improves user experience, and the effectiveness of searching what can oftentimes be hundreds of thousands of posts.

Moderators could even have a control panel allowing them to weight certain terms in certain forums or categories, knowing that words and phrases are likely to be reused often in certain sections of the forums more than others.