Geoff Voelker and Stefan Savage discuss the differences in infrastructure utilized in distributing spam and hosting online scams. According to their research , most email scams are hosted by an individual Web server. Taking a novel approach, these researchers utilized a spam feed method to check spam embedded in suspect URLs to host servers. Their findings were presented in a paper, which has been accepted for publication at the 2007 USENIX Security Conference. A full press release is available here.