The great thing about this application is, weirdly, it is seperate from outlook.
You basically download all the headers of the mail in those accounts, and when you highlight a message the first 20 (default) lines are shown. It also checks the sendees address against an online blacklist.
This program rocks.
Especially as I get 300 junk mails a day. Hell, I hould prob close the accounts to be honest ;p