While Facebook's URL blacklist is extensive, its scale will benefit greatly from the new partnership. Trend Micro, for example, has built up a huge database of malicious URLs and links — it alone scans 300 million URLs and blocks 1.4 billion potential threats per day. Part of the reason this is important is because, as we noted earlier, most "hacks" occur outside of Facebook where you might accidentally type in your password.

Alongside the blacklist update, Facebook today launched the AV Marketplace, a new home for free six-month trials of apps like Norton Anti-Virus 2012, Trend Micro Titanium Security Essentials (PC), and Trend Micro Smart Surfing (Mac). While McAfee has offered six-month trials in the past, this marks the first time Trend Micro or Symantec has offered this kind of deal. "We believe that arming our users with antivirus software will help empower them to stay safe no matter where they are on the web," Facebook said.