Mark,
I don't think it's the forum, but instead, you've picked up some malware on your computer. I had what sounds like the same thing a couple of days ago, before I came back here after a bit of an absence. Certain words would be hyperlinked with a half circle and arrow beside them. To fix the problem, I went into Control Panel and found an ad program on my system that I hadn't installed. If the issue is a recent one, you should be able to tell the program by the installation date beside it. I removed the program and then went into each of my browsers and re-set them to their default settings, and that eliminated the problem. I didn't lose any passwords or anything else when I did the re-set, but your mileage may vary.
Cheers,
Chris