Social networking sites are becoming victims of their own success.
Hundreds – even thousands – of users can share information faster than ever before, providing a more connected world. However, as more people use these sites, they become an attractive target for hackers. Most recently, we saw a relatively new style of exploit on the popular Tumblr blogging platform infecting the web application itself with a self-replicating worm.
read more.......http://www.scmagazine.com/tumblrs-troll-a-wake-up-call-for-social-networks/article/275566/