Tumblr admitted it was hacked by the racist anti-blogging group that goes by the acronym GNAA.
A few thousand blogs were affected by the malicious worm. All affected blogs automatically posted a racist spam post. The virus effect was short-lived. Tumblr has close to 8 million users that could have been infected. In order to get the virus a user needed to be logged into Tumblr and use a browser different than Internet Explorer.