Community themes v child themes non-Studiopress

[GinnyBee]

I wonder if someone can clear this up for me. I've been browsing the resources section and see there are various themes listed, some are under community themes and some are under child themes which are not developed by Studiopress. (I'm aware these are all not by Studiopress and not included in the Pro package)

Am I correct in saying that the Community themes offer support in the relevant part of this forum?

But what makes one theme a community theme and another not? What would be the main differences to a user/purchaser?

Lastly, how would someone become listed as having a community theme??

Thanks