Hi kakeneti
Welcome to AppThemes.
OK, Here we go...
1. ClassiPress is a theme, and then some. It has been designed from the ground up for one specific application, and is both self contained and extensible. It really is more than "just" a theme.
2. Yes. Viewers can respond to ads via a form that hides the ad owner's details.
3. I'm not sure if I understand this question. If by "chat" you mean "comments", then, Yes. Comments can be used within ads if you so choose. If you are referring to one of the 200 plugins available that are related to the term "chat"... maybe. Due to the complexity of ClassiPress, we cannot guaranty that all 3rd party plugins are compatible.
4. I would go with a host that is scalable. You should be good with that for a while, but if you are moderately successful (and we hope you are), you will need to add a few thousand ad placing customers to the mix. You may want to check out one of our
hosting partners (and if you sign up, we'll give you 50% off).
5. No problem. Beyond the Pre-Sales forum is a very large, vibrant and quite enthusiastic international community of users from all walks of life and skill levels. It was the community that sold me on ClassiPress several years ago.
6. Yes. Although built-in "mobile optimization" is something that is still on the drawing board, there are customers that use the popular plugins that accomplish this.
I hope that helps.