What is ShareLaTeX?
Real Time LaTeX Collaboration The version you are looking at is always the most up to date. Watch other users update the same document you are working on in real time.
100% Online LaTeX Enviroment We worry about the LaTeX enviroment, not you. We look after your data, you just have to find a computer.
No Lock-ins Export your entire project at any time.
Compile LaTeX to PDF Online One click and your project is compiled into a PDF.
Simple LaTeX Debugging We convert those horrible long logs into simple to read errors telling you just what you want.
Customise Customise the editor with a varity of themes as well as using basic Vim or Emacs key bindings.
Source Code and issue tracker: https://github.com/sharelatex/sharelatex
ShareLaTex is now part of Overleaf