How is it better than using a hosts file like this one?
http://www.mvps.org/winhelp2002/hosts.htm
If your goal is instead to block the ads completely, I still prefer to use AdBlock Pro and let them manage the block list, rather than clutter up my hosts file.
I was shocked to see that, when you are on paypal.com and click to register a new account, it routes you through some dubious ad network. Scary shit.
Saw this behaviour on another rather large site the other day, can't recall the URL though.