For a horrible example see: true-betas.org

It’s not just that site, there’s heaps out there… The whole point of a portal is for content, so why take the content directly out a forum when you can just GO to the forum and read it there? It doesn’t make people want to stay on the site any longer, because if anything, they don’t notice the forum link at the top and leave, or leave because the few posts they can see aren’t really relevant to them…