Comment It's the users, stupid (Score 1) 176
Gmail's biggest advantage is sheer number of users, not the actual technology. Their filtering would be pretty effective if all they did was learn from their users hitting the spam button.
If you get a spam into your inbox, chances are that hundreds or maybe thousands of other gmail users read that message before you and marked it as spam. After a certain number of these manual filtering events, Gmail can simply blow it out of all other mailboxes.