I've only had my blog a few months (so I'm sure this is normal) but I've gotten multiple users that have registered with suspicious names (just a random combination of letters and numbers) and emails - within a day of one of the registrations, I was somehow locked out of my own site/nothing would load (eventually I was able to login, but there were still some things that seemed off)... I deleted that user (a support forum on a different site suggested that maybe users could 'get into' my site and cause some damage that way) but now every couple days (for the past few weeks) the user keeps registering again!
1) Is it possible for registered users to hack into my blog (easier than non-registered users) and do damager?
2) If so, is there anyway to stop them/any safegaurds I should use?
and 3) Is there anyway to permanently block a user?