Moon Edit is a text editor aimed at programmers whose main feature is that more than one user can work on the same doc at the same time, which is likely to make it an interesting alternative for teachers, students, and programmers.
'So how does it work?' you may ask. First you have to upload the doc to your server, enter the details needed to connect, and done. All connected users can pick a separate color to underline the text as they type it in so that each addition is clearly identifiable to all.
In terms of text editing, Moon Edit includes the standard tools: editing functions, find and replace, etc.