While it was definitely interesting to look at the reasons why Facebook was able to crush MySpace in the social networking world, it's also true that there are more and more questions about the sustainability of Facebook. We recently wrote about the claims of a potential toolbar scammer being one of Facebook's top advertisers, and while Facebook denies the company has ever advertised with them, others claim they're still seeing those very ads. Either way, a new research report suggests that scammers are increasingly targeting Facebook -- with some level of success. It appears this may quickly become Facebook's next big challenge. Historically, Facebook was more immune from scams and spam due to its private nature. However, as the company has continually pulled back on privacy and pushed people to open up more, it's also allowed in all sorts of openings for spam and scams.