There is a lot more value to collaborative features than just giving other users the ability to edit code behind your back. I implemented the collaborative Jup

There is a lot more value to collaborative features than just giving other users the ability to edit code behind your back. I implemented the collaborative Jupyter notebook capabilities in https://cocalc.com https://cocalc.com back in 2014 and have observed, rewritten and used it since then, and there are many additional benefits to collaborative features. (1) If you have more than one computer, you can open the same notebook on multiple computers at once. This better uses your available screen real estate. (2) Similarly, you can open the same notebook in two browser tabs, which provides two views on the notebook at once. This is very handy when working with the long linear format of Jupyter notebooks (e.g., writing documentation near the top and running computations near the bottom). Some notebooks are really long with hundreds of cells... (3) The underlying functionality that makes implementing collaboration possible also enables saving the exact edit history of the notebook. With CoCalc at least, Jonathan Lee added a history slider (like in Hackpad) that lets you easily browse the history of all edits to a Jupyter notebook. This can be very useful if you delete something, or want to know how your notebook got to its current state. It's also useful in case somebody really does "edit behind your back", since you can revert the changes. (Regarding shortcomings of Colab: CoCalc is similar, but works in Safari, Firefox, mobile Safari, etc., and has support for all popular kernels, including Julia, Anaconda3, R, etc.)