The company we obtain our ads from was bought by USA Today and they required us to put that statement in our footer.  

Basically our traffic numbers, along with 1000's of the other sport related sites "in their network" can help them sell higher priced ads which are targeted at sport fans.  It allows them tell companies they can run ads that get viewed by as many eyes as Yahoo Sports or ESPN.com.

http://www.prnewswire.com/news-releases/usa-today-sports-media-group-acquires-big-lead-sports-digital-property-and-fantasy-sports-ventures-137956063.html