I always have ads. They typically appear on the first post, and several scattered throughout a thread. I assume it's because I haven't paid for the "increased forum availability" or had a large number of posts myself? The annoying part is they break up a person's post (ad is in the middle of text).
The forum is free!
The ads are based on your personal search history.
You can clear your browser, and download a free program called malware bytes.
Casey
FWIW, I am designing an ALS app for Google Glass
Max