Wow. You are doing about over $45CPM per ad unit. That sounds really good. I wish I was in that area. But I think the principle still holds - if you are going

Wow. You are doing about over $45CPM per ad unit. That sounds really good. I wish I was in that area. But I think the principle still holds - if you are going to be replacing ad views that are automatically and reliably earning $45 CPM then you need a reason to do it. The 2 good reasons I can think of are 1. More money. 50% more to make up for your extra costs 2. You want to diversify your income so if adsense ever went bad you would be in a better position. Maybe if you had an automated ordering system where people payed you upfront you could go lower but otherwise I just don't see how it is worth it. I agree with the sponsorships idea though. Let me know if you are keen to sell me some of that ad space for less than google returns :)