It'd be really cool to have a Student/Teacher or Pair-Programming mode.
Here are the several modes of multi-user editing.:
This is a mode where both see the same buffer and their cursors are linked. Only one can type at the same time. The scrolling in the buffer should be the same. Suitable for simpler pair programming.
This has two cursors. Similar to google docs. Each user controls a cursor and can edit independently. Suitable for advanced pair programming.
This is similar to Single Cursor except that only one person can edit at a time. The other can still move around the buffer to read other parts. There needs to be a button to snap back to the scroll position of the editor, though. Suitable for teaching.
This would be pretty awesome.