July, last year, Sum 1 to N said the following:
Someone somewhere should make a Web 2.0-ish collaboration site where people can do math together. Maybe like an IM service meshed with LaTeX capabilities, but without the coding hassle. Point-and-click type stuff. And an ability to save the notes and do projects together. Oh, and some basic graphing capabilities. And the ability to export the LaTeX code, and import and share MATLAB, Mathematica, (etc.) code.
Well, close enough.
Also, if you happen to use a Mac, there is always Adium X, which Cosmic Variance happily informs can be made to support LaTeX equations. You can even click the equations, inter alia, and get the raw TeX back out of it if you want. Super!