I haven't seen much information about exactly how the community feature is going to be implemented. I worry with moderation, community problems can result in situations like the /r/btc and /r/bitcoin debate.

The communities should include features that allow users to find popular posts from the past (especially where voting is still open). This would make well written posts more visible to newcomers. As of now, the hot pages are filled with bot-upvoted junk. A best of the week in the community a new user is interested in is exactly the type of content that could get them hooked. Features like this are really important when the community is small and ther is not enough quality content to fill all the pages.