Dittos, James! And, well said.
Joe, Presenting only "relevant" ads is a great ideal, however, the sponsors/advertisers have to be willing to spend money on advertisements. The "relevant" sponsors are not. In advertising, you take what you can get, especially when it comes to online advertising.
It's like billboards on a highway. You only see the products advertised that someone is willing to pay the 'buy-price' for the billboard. You don't ONLY see the products you personally like.