I have heard around that if you have a website that is primarily a forum and you do not have a static homepage, it will ruin your page rank. Does anyone know if this is true? I know that flash pages ruin your SEO, but what about forum pages?
It's false. PageRank is determined on a per-page basis by the number of links pointing back to your pages. A forum index acting as a home page is no different than a regular home page for this purpose.