By posting in different communitites we actually try to draw attention to the project. It's a good idea maybe to host some contests and work together with other communities.
And here are we, members. I regularly reblog/rehive most of the Liotes posts...
That's actually a great way of promoting the project :-)
Thanks a lot for your suggestions!
Yes, but (from my experience) you don't need to post from that communities. You post from your community and have tags of other communities. All posts with that tag appear in that communities sites...
btw: I'm writing resume as archonapp for ArchonTribe about some communities, rewards, etc, just an example, I don't want to advertise anything, check it here, maybe you'll get some ideas ...