Weird 'users' being created ....

Just again wondering why I get 2-5 'users' a week created on my CMS with obviously bogus names like 'dwLckaaIEsRgLZPn' and stuff and fake email addresses .. I guess it's prolly some bots or idiots who want to post crap on my webpage... To you bots/ppl ... screw off I won't unblock those users anyway ..