Re: Server requirements?
Shared hosting works fine assuming you have a good host. As you get more forum activity, you would need more server, and shared hosting is not going to be enough. For starting out though, bbPress works fine on a shared host.
I’ve been using 1&1 (affiliate link) for 4+ years now without any trouble at all running WordPress or bbPress or anything else, for that matter. If you get an account on a shared host, I would recommend getting one with ssh access to a command line. It makes a lot of things much easier. If all you have is FTP access, that’s OK too.