I followed what you were doing at app.net with great interest when it launched. We were also building an app platform, but with a very different focus.
https://qbix.com/platform . All our business models are NOT ad supported. Ads are "begging" the user to spend their time and maybe spend money. There are many ways to make money if you make apps for local communities.
We sort of took the tortoise approach to development, and this seems to have helped solve the chicken and egg problem with the userbase.
I will email you about it.