Just encountered this recently, to update my technical knowledge. Typed the address , to see this Screen.
At first i was a bit confused, and waited for the page to redirect by itself.But later i saw the Link , continue to Pcworld.com.Thank god, the site was the original. Only the home page was altered. There is no popuups and irritating ads.I would tell that PCworld forum could be one of the best websites in the Internet world.