Selected answers from the Dumb SEO Questions G+ community.
Alan Bleiweiss: Same primary process and rules. Biggest challenge with forums is setting rules for what to allow to be indexed and what not to, where you block crawling those because on a popular forum you can end up with mass scale duplicate content and where eventually, crawl budget really can be wasted without those rules in place.
Nicholas Bodell: As in how deep ie page 1, 2, 3 of the topic should the crawl go?
Alan Bleiweiss: As in "how much unique value does this page have?". A single post with no answers or with responses that don`t answer the post question or are just repetitive, is junk for SEO. A single URL that is just an answer that also exists on a more complete page, is junk for SEO. A post that is semantically the same as previous posts, is junk for SEO.Those are the biggest examples.