I pretty sure this is against the TOS, but i just want to make sure. !) Could I put my ads on someone elses site while they are putting their own ads up too? 2) Are you allowed to share ad space? Like I put one of my ads on your page, vice versa, and get both of our site's impressions?
Hmm, I don't see why not. If you keep the ads limited to the number set by Google. Read the TOS for Adsense again to get your own feel but I think its ok. I was going to do something similar but we were going to use a rotation script instead.
It's allowed as long as you don't exceed the maximum number of ads allowed per page: https://www.google.com/adsense/support/bin/answer.py?hl=en&answer=32855
you can do it, but keep in mind to keep the number of adsense ads and link units as allowed by the TOS