Not sure what you are referring to, but yes, there are free forum hosts and free blog hosts out there on the net. However, integration with Office Live Small Business is not that great as there are no native blog or forum applications for it. The way that many people are doing to "integrate" OLSB with forums or blogs (other than the RSS feed from Windows Live Spaces) is that they use an IFRAME to add a blog or forum website (because the blog or forum is hosted elsewhere) in their OLSB website. The really bad thing with that approach is that it does nothing in terms of SEO for your OLSB domain. as search engines will not associate the content in your forum or blog (since it has a competely different URL) with your domain on OLSB. As you may be aware, blogs and forums generate an enormous amount of content and are updated frequently, and saerch engines just love indexing through them.
So, be aware of the pitfalls. If a forum is just a nice addition to your website and not something you would consider as important, then it's fine to use an IFRAME. But if it's optional and you don't expect a lot of traffic to it, then why have it at all?
Royster