Just saw this story over at The Reg. It's about a site called "Artists against 419" which has catalogued 80+ sites which is used for scamming people. It has created a page which is loading up images hosted at these sites, and reloads every 2 minutes. This accounts for 410kb of files transferred. Not much, but since it happens every two minutes, it does rack up. And then considering most cheap hosting services only allows 1GB of transfers a month, it will cost the scammers quite a bit if enough people can be bothered. So check out the story and the site.