Hi guys, this little gizmo is nearing completion for its first release, if you're interested or have any comments please let me know. Shameless plug follows...
With open source DutchPIPE software, web developers can make virtual multi-user environments. Each web page becomes an abstracted environment or location where visitors and other items on the page are visualized. This status is retained as visitors move around. A lot of real-time interaction is possible. The result: Persistent Interactive Page Environments. DutchPIPE uses AJAX and the DOM for the browser - it works without Java, Flash, plugin or firewall adjustments. On the server, PHP is used.
The site becomes an abstracted world or universe populated with objects, which can be moved into or out of eachother and perform certain actions. There's only one world with one set of objects - if you drop something on a page, someone else can visit that page, see the object, and carry it away elsewhere.
http://www.dutchpipe.org/