I think to be able to say you're a "decentralized alternative to YouTube, Flickr, SoundCloud", you really need some way to search across all the servers in the network or at least interact with them and as far as I can tell, that doesn't exist. In the tour there's not even any mention of decentralization that I can see.

Is there something I'm missing?

Also in terms of self hosting, something I'd really like is the ability to point it at a pile of files and have it ingest them in place. Any idea whether that's possible?