Server fees, staff wages, and all the other things involved in making a giant infohub like Allakhazam actually function costs a lot of money. That money has to come from somewhere. A lot of smaller sites use Google Ads or other things like that... but for MMO-related sites, that almost always ends up so you are promoting RMT sties just to function more often than not. Any MMO-related site that you visit that does not appear to have advertising is either A) set up on a small scale, probably either on a free blog or forum site or a privately leased URL, or B) getting funds in some other way, such as donations.
Anyway, since the site has to fund itself somehow, those who choose to use it but not to help support it monetarily will be subjected to ads because that's the only way money can be made off of them. This may sound cold, but without funding, the site would still be just a small EQ message board and nothing more.