YAHOO! Answers says Tumblr isn’t any more virus-prone that other random web sites, but also offers this dire Tumblr warning:
One bad flaw is it is full of annoying pretentious teenagers who don’t like new people coming on to the site. They also complain too much, and reblog pics of legs and food over and over again. They make Tumblr less enjoyable, but it’s easy to avoid, if you follow like-minded people.
Legs and food. lol.