One nice feature of IPB is the ability to send your status updates out to Facebook and Twitter, if they are linked with your account. I have a professional account for each of these sites. I never visit them, but I have a lot of followers on them. I can just update my status on my site, and it goes out to Twitter and Facebook, and to all my followers. It's a good way for my users to spread awareness of their projects on our forum, and it probably is good for SEO.