Heather,

your editorial preferences would be having the sponsorship announcement on the bottom, but you could accomodate the whiners people who prefer to have it at the top to record their preference using purely client side techniques (widely adopted HTML5 DOM Storage). Basically:

Look at the source; it's really not hard to implement, and as it's client side, there is no additional load on your server(s). Cheers,

Sylvain.