I'd think the posts get stored in the chain. On the other hand I've seen there was a few posts deleted. That speaks for not stored then ... the idea to store it "forever" in the chain is used by some coins. Not sure if they do here, but for good content that makes absolutly sense. And in general for this project would do as well.
But I'm seriously n0000000000000b with code ...
Would be nice to get that answerd by someone who knows XD