For the most part, Google taylors its ads to each individual user. There are exceptions to the this and sometimes google will show ads at random, especially if one does not have a google account or if he/she "opts out." Otherwise, ads are based on google searches, websites visited, even items ordered on amazon. Google does this by "cookies" on your computer to keep track of your online activities. It then taylors its ads to reach the best audience (ie, those most likely to click on the ad). So, the ads that you see will not be the same as the ads someone else sees.
That being said, this site does not have any control over which ads google shows. All the administrator can do is block certain ads. That is why he has requested that the users report ads they deem questionable.