Most forums have problems with spammers. I assume once bbCommunity starts rolling, it will have its fair share. However, I wanted to share thoughts on how to stop spammers. These aren't proven, but they would have stopped 90% of spam I've seen.
1. Captchas : These are those annoying little things where you have to type in the random letters on the disco background. Although these will stop bots, they will annoy your users like crazy. To prevent it, I'd do it one every 5 posts for new users, once every 10 posts for older users, and always for a new thread. If you do, use www.reCaptcha.net , you type in 2 words that were scanned in and could not be read by the computer. 1 of them has a known answer from previous checks. As people use this, they help digitize books.
2. Flood Control. I hate this entirely, but it works. If your site is bad enough to need it, please, for the love of freedom, ONLY LIMIT THREADS! If you limit posts per hour, I will hunt you down.
3. Better Filter: Try removing spaces and such before filtering. You'll probably have to program something, but it will get a lot of the "da mn"'s on your forum.
Personally, I'm going to let people swear on my site, but only use words on a "list". Each person sets a "vulgarity level" to filter out which words they don't want to see.