No need to sign up for anything. #palnet runs on top of Steem. Using the tag allows you to get upvotes from PAL holders. DTube has already its own PALTube. Soon we have other Tubes, for Anarchy maybe.

Keep in mind that DTC tokens on DTube are still testnet and will disappear again. But you will get airdrops for being active on DTube. And have you seen that you can now post just a YouTube link on DTube but still get the FULL BENEFIT? I got a huge upvote yesterday on a YT video from DTube.