forums were always valuable for one job, getting a tier 1 page crawled. a profile or a post that links to your web 2.0 gets that page fetched inside a day, i have run thousands of them for that with GSA SER /Xrummer AI and never once cared about the link itself. if the AI engines now read the same forums for opinions thats a second use for the same platform, but i would not confuse the two. one is a crawl trigger, the other is brand talk