Thanks to @itwasntme223, I finally got on #PeerTube. First remarks:

- There's a dearth of stuff to watch. Some travel #videos, some gaming, lots of politics and little else.
- Federation between instances is poor, perhaps because people have little reason to follow each other across the network.
- Instances don't have beefy server farms behind them, so transcoding takes time.
- Tagging is weak and little used.

On the plus side, I have things to post that people want to see!