X-rated question for techies.

[jdj]

What makes porn pop-ups come up on your screen? (Ads from nude women to buy pictures or whatever). My Dad is having this problem. I've never experienced this, but it's on some websites where he plays games like checkers and chess, and people all over the world play on there as well. He has played with people from the Ukraine and Africa, etc, which he really enjoys, but he's pretty religious so this is offensive to him.

Does anyone know what is going on, is it something allowed by the owners of the website, because he has spy sweeper and pop-up blockers...any input anyone has will be appreciated.