Timely for me as well. Another reason for adding an additional version number component is this: I use an open source library that I need to fork. Since the library uses the `patch` number component, it's hard to release forked versions to NPM without having conflicting patch numbers.

For example, if the library is at `0.15.4` I don't want to release my updates as `0.15.5`, `0.15.6` etc. because when the main library updates to `0.15.5` we have conflict/confusion. Instead, I'd like to `0.15.4.1` to indicate my `.1` update to `0.15.4`. When they update to `0.15.5` I can merge and release a version at `0.15.5.1`