We haven’t started using forum web parts yet but look forward to doing so soon.
However, from the way forums work in Kentico devnet, it seems like there is room for improvement.
When I search for a term like bizform, for example, I get 14 pages of results because the result set does not appear to be threaded. The resultset appears to show every post that has the word “bizform” rather than a single instance of the thread that has the search term in it.
A better implementation would be to show a result set of the first post of each thread that has the search term. You could even parameterize this behavior if you see a value in showing all hits with two radiobuttons: “Show all posts”, “Show first post in each thread.”