After digging around online for awhile, I finally settle on a few plugins for bbPress than does a good job at weeding out web spammers. Sheesh, these people really cause a load of headache for any would be webmasters, fortunately there are many tools created by very smart programmers to weed out these bad people online.
I finally found some good plugins for my bbPress that could do just what I wanted:
1. Weed out bots from humans during the registration phase
2. Mass delete the existing spammers who now number about 5000!
The few plugins that I settled for are:
a. mass delete users
b. recaptcha for bbpress
c. human test
After giving a quick spin after installation it worked flawlessly! So one more up against those pesky web spammers.
If you plan for a lightweight software to build a forum website, bbPress is a very good recommendation with its Akismet spam busting ability and a little help from the plugins above, making it one of the best new free forum website application around!
To get bbPress goto http://bbpress.org
The plugins are in the "Extend" tab.