DO NOT click on any links on posts like this:
LOL look at this girl’s mean EX posting nudes on her tumblr
LOL this girl has nude pics all over her tumblr, looks like someone should have been nice to their EX girlsinthemirror.tumblr.com
The link above actually links to a fake Tumblr login page (http://com-archive.us/login/index.php) that steals your login info when you try to login.
It seems to be working too because I’ve seen a bunch of these posts on compromised Tumblr accounts.
I suggest using a browser extension like LinkPeelr to check links before clicking on them as it’s not hard to fake a link. Also pay attention to the URL in your address bar before you ever login to any website.