The new Shoutbox should not create pop-up ads. If it does please let me know.
The seemingly random double underlined words in the ShoutBox are InfoLinks. This is advertising, so don't click it. The other advertising is a moving banner of adverts in the bottom of the Box. You can cancel this by clicking the [x] but it will re-appear when you go to another page.
This is the best compromise of a free ShoutBox that I have been able to find on short notice. I will keep looking for a better one.