how much of that may be due to not having enough relevant inventory? there's definitely a chicken/egg problem involved in targeted ad serving, but you'd have thought someone (apple?) might have been able to crack that nut by now.
In my particular case I don't think there was an inventory limitation issue. Reason is websites with Adsense addressing the same niche were serving extremely relevant and targeted ads while my Android app with Admob just gets junk. The obvious question is how does the Admob banner know about the app's contents? On the Admob site there's a note saying that the app's description will be used to target ads. However this doesn't seem to work or I'm misunderstanding. Either way my ads still suck.
