It has something to do with the way the servers work and pick up paid advertisements that are ***igned to sites by topic. Sort of like popups on your PC, but a bit more complex.
The wonders of google and the world of advertising media.
To be very blunt. If those of us who say we are supportive of this forum, where to take advantage of the financial aide request thread and willingly kick in a few dollars, the site might be able to afford a dedicated server a lot of that would be eliminated. I can not say all unwanted ads would be gone, but it would most likely eliminate some.