This would be a great feature to be able to ban users (especially by email domain). I notice I have a lot of bogus users that get registered (they never post any spam) but they are always from the same email domains and I have to clean these out of my users table weekly. It would be great if I could just ban any users with the email domain of '@makeabilliondollars.info' or '@duiattorneylosangeles-lawyer.com'. These are just two examples of domains that people register bogus accounts and that I have to go in an clean up weekly. It would be great to be able to block any people who are registering with those domains as email addresses (and a lot of other domains as well).