collaborative text editing

[justice]

I'd like to edit text together with someone, either using Windows live messenger or using a website. Is there any site that makes this as easy as possible to do so:

No registration. just an identifier to return to it later. We have enough accounts.
Live updates when text is updated, i want to work on the same document 'live': no having to reload it to see changes, and in the same window not like chatting.
A way to save it and return to it later as the document will require multiple sessions of collaboration.
I need to get the information out in text editable form afterwards.

Anything else is optional. But I can't find anything looking for text editing collaboration. Can you help?

[justice]

WLM allows for using a shared whiteboard - only saves to its own data file meaning i can't get the information out. also more focused on drawing, not so much text editing.

you can also use it to share an application, for example notepad. This works but only one person can be in control at the same time. Guess that's alright and migth be worth a longer look at. Not sure if when not in control I can use any other app though. That migth be a dealbreaker.

http://en.wikipedia.org/wiki/MoonEdit might do what I want, have not checked it out, requires installation of software which is an issue.

[nontroppo]

You could see if a Windows-compatible SubEthaEdit is out yet (it wasn't last year, but who knows):

http://www.medialoper.com/columns/thats-what-i-like/thats-what-i-like-subethaedit/
http://www.codingmonkeys.de/subethaedit/

[justice]

Right that's it I need to make the next two pc purchases macs. It's impossible to properly write anything together without a Google / Zoho account online. Btw I was unsuccessful in application sharing between a vista and xp pc running the latest messenger.

SubEthaEdit runs on bonjour which is now installed when using ITunes / Quicktime so this means it should no lnoger be the roadblock for a related windows app.