Imagine if you combined Garry's mod with Minecraft, only better. This game will have an in-game editor, so you can make changes on the fly, and have your players see them immediately. Need some trees? Just open the editor, draw a quick texture, make a new block type, and voala: Trees. No need to send .mod files or restart the server, everyone already has your changes.
I've rewritten a ton of code, signalling the end of the "proof of concept" stage and the start of "let's start making some games in this thing" stage. Particularly, textures, packages, and block types are loaded (from an XML format), instead of being hard-coded, and GUIDs have replaced the string names. All of that is more than you need to know, as it doesn't effect much in-game
What it means to you, is soon you will start being able to save the changes you make in the world, and pull over other "packages" that your friends make. Eventually (thousands of years from now, or next week, whenever) if you and your friend both make a change to the same package, you can automatically merge the changes and the computer will be smart about it.
Now, off to fix every editor!
A large update for Gwen.net was sent earlier this week. Hopefully they approve it so I can work on multiline text boxes.