F-Secure has an article about a worm which targets sites such as bebo.com and facebook.com

The author of the article, Christine, posted some sample comments such as “Are you sure this is your first acting experience?” and “is it u there?”

Each comment contain a link which points to Yuotube, not Youtube. The site will ask the user to update their Adobe Flash player but the update is actually a worm which is detected as Net-Worm:W32/Koobface.CY.

The other websites that the Koobface worm targets are myyearbook.com, blackplanet.com, myspace.com, and friendster.com.

Source: F-Secure