Well Microsoft Adcenter promises more ad dollars thanks to its compatibility to social networks socialads systems like Facebook's).

The only fight back for Google would be to do the same (Which I understand that's what Maka-Maka is all about), or launch a campaign on the privacy issue behind the use of personal datas to tailor targeted ads (what they call non-personally identifiable data like your IP or your profile info).

I say, people prefer to go with Google,unless Microsoft promises more dollars.

SocialAds may prove to be a strong competition, but i think Google will still come out the winner, with Facebook it's hard to generate targeted ads as the users are mostly generic with a simple intention of using the website to be "social" and have fun, it's a lot better to use Google to create targeted ads, an important factor to consider in any advertising strategy

Facebook or any other Ad network still isn't able to compete with google's ads. Heres the guide for developers out there to get Google Quality ads inside their Apps.

http://www.infinitepixelstudios.com/dev-tips/Google-Adsense-in-Facebook-Apps.html

I've got what essentially is a walk through guide, hope those reading find it useful. Difference is this guide shows you how to get relevant ads.