I am getting many new user registrations that I know are not legitimate. They are all coming in with what looks like a bogus hotmail email address, something like firstname.lastname@example.org and user names like chelseao3j. They look like they're being generated by a script. I'm getting about 5-10 registrations like this per day.
Is this something I should be concerned about? If so, are there steps I can take to stop this activity?