FontForge can now allow multiple people to collaborate on designing a font in real time. This is all still rather alpha level code, and in fact the pull request including this code was only pushed over the fence in the last hour ;) If real time collaboration sounds interesting to you, or something in this post seems of interest, then you might like to attend an upcoming Interactivos Workshop which is right after the Libre Graphics Meeting in Madrid (10-27 April).
At interactivos I will be expanding on the current collab code and discussing future directions and possible cross tool network specifications to allow different font tools to talk to each other. Even if you are not convinced that you want anyone else joining your collab session, you might like something like a Web sink watching your work and updating a page on your tablet as you modify the font so you can see in near real time if changes are going to work well on a target device and design or not. Why burden your workflow having to have your local fontforge export to an OTF and slow you down when a server can do all that for you in the background. There is no reason that the processes in the collab session can't all be running on your behalf.
If you are running osx then I have a binary drop for you which bundles all the needed stuff for collab at:
To start a server select the menu item Collaborate/Start Session... a dialog will show you the IP address the server will run on so you can start fontforge on another computer (+other OS) and connect to that address using Collaborate/Connect to Session...
Things are in very early days and focus has been only on the glyph view. It seems that there is some fluff holding the undo system from working on the metrics view (thus on kerning etc).
The design uses FontForge's undo/redo system to know what the changes are in the font, and since those changes can be serialized to an SFD format that code is reused to send and receive the undo information across a zeromq broadcast server.
The design is inline with the MCT (Merge Enabled Change Tracking) for ODF that is up on the OASIS lists. In FontForge's case, s baseline full SFD snapshot and sequential fragments thereafter describing updates.
If you are compiling from sources then you'll need czmq and zeromq version3 development stuff installed. Then grab master from github and enjoy.