[FoRK] Rpad? Web-based math collab?

[Jeff Bone]

Anybody using this?

   http://www.rpad.org/Rpad/

It looks like a fantastic idea, perhaps not fully baked.  I've been  
waiting for somebody to (a) take the wiki-as-app-server idea (which  
this isn't quite) and run w/ it since JotSpot got assimilated by the  
GoogleBorg and apparently entirely defudefangedsed (thank you Mac mail  
edit widget, but it's an amusing enough pseudo-typo to leave in) and  
(b) come up with a reasonable Web-based collaborative-space math  
notebook, preferably open source, preferably not the Sage hair ball.

I mean, clearly Google should be doing this.  Buy Wolfram, open source  
Mathematica, and provide integrated Mathematica and Google Notebook.   
Barring that, build R into Google Notebook;  numerical and stats stuff  
has more practical application to more people anyway.  But I'm getting  
tired of waiting for the Google-Herd-of-Cats to get their feature sets  
aligned, I mean, hell, we don't even have a consistent tag / folder /  
bookmark / feeds etc. thing that works reasonably well across their  
apps.  An operating system factors out common functionality, dammit!

Anybody have any pointers to similar things, perhaps more usable?

jb