The effects don't seem to be that awful. It will install some toolbars and stuff like that against your will, which is very annoying, but at least you don't risk losing important data or damage your computer.
Mediafire and 4Shared are known to host this Ad (which is still unknown), so for the next couple weeks try to use them as least as possible, as you have the chance of getting a damn Malware.
I was told that numerous other Music Blogs were experiencing this. The Trojan is coming from the Download Links not the Blog itself. The Blogs have no influence on it at all.
Also it seems like this Ad is also running on Youtube and Amazon.
This Link, here, will explain in detail how to get rid of it, once it gets to your computer.
The name of the file is XVidSetup.exe