Our ad system is run by Google and is based on what they think you will like. Also, we have paid advertisers who sponsor us for a month. You can change your preferences for the Google ads but not the sponsored ads.

Read more about it here:
http://www.google.com/ads/preferences/html/about.html

Change your ad preferences here:
www.google.com/ad/preferences

*Edited the ad preferences to the correct URL.