global banning system
 

what if we could create a simple mod using an xml file that contained a collection of usernames of members that have been banned. have it connected to the registration process and all that. the key is that it would be accessible to anyone with vb. so if they wanted to use the list for their board. the problem I see with my science forum is that if some other science board banns a member, then they come to my site and vice versa. this could solve that problem by any number of sites sharing a ban xml file

If you use "usernames", it will not very efficient as banned user might have a different username, or worse, a different user might occupy that username in the other board. I think the system might be more efficient if you used email address of the banned user but I'm not sure if it would be against privacy to distribute the email address your board publicly to other sites.

I think you already thought of hosting a private forum where only other site admins have access and you share your banned email address there?

right, because my forum is part of a science network, but I understand your points