It has been now 3 days that I noticed the same ad is appearing on the Top-Right side of this forum. Below is the screenshot of it. Are you guyz seeing different ads or seeing the same ad like mine?
This is called Targetted adsense advertisement. You can also have such "site specific" campaign from your adwords
It is just targetted advertisement of adsense er.. by adwords! You too can advertise there if you want http://www.digitalpoint.com/tools/keywords/advertising.php