One thing community owners may not be aware of is that their community does have a wallet, that the account can vote on post that people post in their community, this may give a little more incentive for authors to start spreading their post out. I have been actively trying to spread my post out to various communities as I believe they can form a solid backbone to the HIVE Block Chain.
The reason so many post in GEMS, OCD, and Curie is because they are known place to maybe get a good vote, So as the owners learn and build an HP balance in their community perhaps people will migrate to posting in communities a bit more.
I am concerned a little bit about the cross-posting, and I do think that Authors should not be doing it, but if a community owner cross-post something they feel fits well with their community then I see no real issue with that. (other than my accidentally voting on a cross post that is from a still active post).
If when I ever get to an HP level where my community can leave a $0.030 vote on a post I may actually start looking for authors.(not really, mine is just for testing purposes).