Dakka does not allow any third party advertiser code other than google, the rest just use static links and images. We dont allow any scripting in any forms either so the chances of dakka ever giving you a virus are incredibly remote. I keep a very close eye on server security and know whenever anything happens so there is no risk there as if we were ever hacked the first thing I would do is take the site offline and move to a new server.
hellsguardian316 is probably correct in assuming it is another virus, a link hijacking attack or other non-dakka related source. I would strongly recommend not using IE at all, and instead install firefox (it will import all your bookmarks happily as well). download it free from
http://www.getfirefox.com
AVG is also a good product to use if you are on windows and is also free.