I had read in Google's help forums that the ad-swapping technique I used as a basis for AdPie is already in use on multiple sites. However, to be safe, I inquired with their technical staff anyway. This is my email, and ensuing positive response:

Hello Google,

I am the webmaster for a new mediazine at coloredchalk.com, and I have begun using AdSense ads as a way to generate revenue.

As a way to reward my contributors, I have developed PHP code that will periodically swap out my AdSense ads and replace them with a contributor's AdSense ad so that they might generate revenue for their work without the need for me to pay them directly.

I have seen other messages in the AdSense help forums that use this method and they claim that you have approved this so long as only one AdSense client is displayed on any page at any time. Still, I am contacting you myself as a way to ensure that this is permitted.

Please note that my site policy clearly dictates that users must abide by your policies, and that if I hear of any self-clicking or click-for-click schemes by users I will shut them down immediately.

Thank you for your time. I look forward to buiding a mutually beneficial relationship with the AdSense program, bringing you referrals and traffic to the ads on colored chalk.

Sincerely,
Jason M. Heim

Hello Jason,

Thanks for your email.

I'm happy to tell that the implementation you noted is permitted by our program policies. Please know that any AdSense publisher may rotate his or her ad code with another publisher's code as long as both publishers have approved AdSense accounts.

However, please be aware that every publisher is responsible for the content of a website on which their ad code is placed. If a website is found in violation of our program policies, we will notify any publisher(s) whose ad code is on the website, and ask you to remove the Google code from that page.

To ensure that your AdSense account remains in good standing, I recommend that you review our Terms and Conditions and program policies:

https://www.google.com/adsense/terms
https://www.google.com/adsense/policies

We thank you for your continued cooperation to remain in compliance with our program polices.

For additional questions, feel free to post your question on the forum just for AdSense publishers: the AdSense Help Group (http://groups.google.com/group/adsense-help).

Sincerely,

Sunil
The Google AdSense Team