The new DM Hub is online. You can start posting stuff there! I made an example (Maze Demo) that illustrates some of the features (having one project include another project).
The DM Hub is a superset of the Game Hub. Once you visit it, the DM extensions get turned on for you, so both hubs become equivalent for the remainder of your session. This allows players to be free of all the extra DM stuff that they may not be interested in but it allows designers to conveniently see everything once they go in through the DM entrance. The official entrance into it has not been created yet, but if you click the above URL, it will take you there.
I have mostly finished converting all the hub URLs over to the new system and moving a few things around in the hub. Although old URLs such as byond://polaris/Deadron/DragonSnot or byond://Deadron/DragonSnot will continue to work on machines that already have 'polaris' and 'Deadron' in the cfg/hosts.txt cache, new players will not be able to use these addresses, because they are no longer maintained by the hub.
The new system is a tiny bit more complex but gives everyone greater flexibility. Instead of pointing players to a particular host site, you point them to a particular hub entry, for example byond://Deadron.DragonSnot. You then maintain the internal URL that the hub entry gets translated into.
For distributed games, this doesn't change much, except that the URL looks nicer than the old seeker://hub:id syntax (which no longer works).
For hosted games, this gives a single author the ability to move a particular game from one site to another without having to publish a different URL. The new system is also designed to accomodate 3rd party host sites better. The host servers that Dantom runs are now simply registered in the hub (byond://Dantom.Host.Star.Polaris) like anything else. We create a personal site entry for each user (byond://Dantom.Space.Deadron) that we maintain and point to the actual host server. That way, the user can point their own hub entries to their Dantom.Space entry and we can point the Dantom.Space entry to the site where we are hosting the actual game. Sounds complicated, but it makes maintenance a lot easier.