Social networking sites have been hit mostly by annoying worm, adware, and phishing attacks. The advent of more interactive, Web 2.0-based apps eventually being added to these sites could expose them to more sophisticated exploits. These sites could be a springboard to more focused attacks on enterprises and individuals’ personal data. MySpace has been the brunt of most attacks, including the SamyS’s “friends list” worm that basically added over a million “friends” to an “amyamy list””]
Source: https://www.darkreading.com/analytics/social-networking-gone-bad