We now have our own Worlds.com private server:
worlds.worlio.com

FAQ
Q: Is VIP free?
A: Yes. You do not need to participate in events or pay money for VIP.

Q: What features are working?
A: All of them except for Voice Chat.

Q: How do I register?
A: Use the link above, or go to worlds.worlio.com in your browser.

Q: Do I need the Worlio server to use Worlds?
A: No but also yes. There is a work-in-progress, free software reimplementation of the server called Libreworlds which aims to be compatible with the original software and improve upon it. You should support them as well!
You can also browse Worlds.com without any server by launching in Single-user Mode. You will still be able to explore Worlds, even custom-made rooms from the Internet, but you will need a server to chat with other users.

We now support and use in-client registration rather than our previous account creation solution. This means the process for creating a WorlioWorlds account is almost the same as was official.