Watch your LOGS and you can sort of see who is being blocked and why. I've had 3 or 4 issues, each easily solved. Whenever you have someone blocked: Delete the IPDDB.CSV & IPPBDB.CSV files, as they will automatically rebuild themselves. Also, READ your logs to see what's unusual/different.
One issue was AOL users since they are so heavily proxied, and I had to add an exclusion statement for them to my customsig.inc file.(see my post entitled "Blocked Registration Attempt?" in the ZB Bug Reports Forum on SpambotSecurity.com)
Another was, I use vBAdvanced's
Link Directory Product and I had to add an custom statement for it since it's a product that is external to vBulletin.(see the thread entitled Beta Updates 67 in the Signature Updates Forum on SpambotSecurity.com)
If you'll search for
my posts on the SpambotSecurity forum, you can follow my progress and learning curve through figuring out the little tweaks I've done to ZB BLOCK to perfect using it it with vBulletin so far.
Overall though, I am SUPER pleased with ZB BLOCK and would NOT consider running a forum w/o it, now that I've seen what it's capable of fending off.(i.e. Harvesters, Infected Browsers, Robot Probes, etc) Our monthly BandWidth usage has decreased roughly 75%, meanwhile legitimate users are still free to peruse the site at will.