We've been looking for a good email validation tool for wordpress user registrations to prevent unwanted or spam registrations such as these.  

New user registration on your site Thoughts and Scribbles:

Username: LillaLucero

E-mail: agd_hare @ n s c r e  a m . c o m

To that end, here's a good plugin to do just that.  You'll get a link verification in your email to force the user to confirm their account before it's registered.  The plugin is called Register Plus Redux and is available from the WordPress plugin page.

Cheers,
TK