It's the price you pay to subsidise others who use those services for free. I don't disagree with you, this is a horrible trend. The "race to the bottom" with apps will leave them in a similar state (Oh, wait, they're already like that - Airpush style intrusive advertising, etc)
However, quite a few websites have options in their paid plans (Grooveshark comes to mind) where they disable all ads on their website for you. All we need to do is show how important privacy is to us, and to prove that there is indeed a market for paid webapps (regular webapps like Mail, RSS readers, etc)