Why am I getting pop up advertising on the forum now?

For example : On this thread, the words Online Tools are highlighted and when you run the mouse over it , it pops up an advertisment from Arcade Web advertising. There are several words like this through out the forum.

Does anyone else have this very annoying problem?

I did a full Norton scan and it didn't remove it. Is this something CW is doing or is it my computor?
later Daniel