Since Google has announced that AdSense will now show advertisements from other Ad networks; you are permitted to add multiple Google-certified ad networks to compete for display ad space on your site.

This will help publishers generate more cash, adding more competition into a site. Again, you’re only allowed to add other Ad Networks along with your Google Adsense Ad as long as it is Google certified.

So when you check out your Ad Review Center account, don’t be surprised...