Hello,
I noticed that some time, when clicking on a search result in google, pointing to this website, I get redirected to url4short.info website.
At first I thought it was some kind of CDN, but after a google search I found out that it was a behaviour to be expected in compromised forums.
I put a link to a webiste explaining how to check and solve the issue, if you find you have been compromised.
http://peter.upfold.org.uk/blog/2013/01/15/cleaning-up-the-ip-board-url4short-mess/