How many AdUnits can I use in my Windows Phone 7 applications? I've seen this question pop up a few times across the Interwebs, and a post on the pubCenter blog has just clarified a few FAQs about using multiple adverts across your applications.
It's really simply to understand too, you can have multiple adverts in multiple positions within your app all using the same ApplicationId, since it's only required on Microsoft's side to calculate how much revenue is due for payment on your account. You don't even have to use multiple AdUnits either, you can simply use the same AdUnit, but duplicate it for the different ad locations you wish it to appear at.
Pretty awesome for developers who wish to continue down the path of offering their app for free (or have a free version). Thinking of using adverts in your WP7 app(s)? Check out our recent coverage of Elbert Perez publishing his earnings (set at $30,000) from games on the Marketplace. If done correctly you can earn a nice sum from your hard development work.
Of course, you have multiple advertising options to choose from, so shop around beforehand.
Source: pubCenter Blog