not a bad idea. we will see that problem mostly in "general" communities, but sub-communities would be nice addon.
i am not sure even how 3Speak community works. i think it is not automatic to post there when you post on 3Speak. is it a double post, or maybe just adding a hive-100421 tag?
Everything posted on 3Speak is automatically posted in their community. I think this is the way it should be with dapps especially considering something like Appics where the content is really a different format than the web apps, but in these cases especially it seems like sub-communities will be a must. Or else we'll just run into the same issue.