[smirkley]

There are millions of spam-bots that go out and look for cataloged registration mechanisms they can exploit and register, same bots can also post posts as well as inject home page links in accounts. The bot senders can send these out much more effeciently that human spammers.

You really cant tell if they are bots, but after awhile you tend to be able to recognise them.

The birthdays dont necessarily mean anything.

The built-in captcha, even recaptcha, is flawed and bots can brute force them or recognise the captcha text to get in.

If you have used vbresults spam blocker, you can see that most bots register in 5 seconds or less. Can you type that fast on the registration form?