Hoenerbr already
mentioned online collaboration on page 2. Maybe it is some form of tightly integrated realtime collaboration. Imagine being able to invite other SONAR users to your session from within SONAR, and then the project gets synced between the two (SONAR uploads the full project, including all audio etc). The two will then play back in sync etc, and you can record on either/both.
Lots of technical challenges with that, including latency, both needing the same plugins, similar IO setups etc.
Maybe a more limited version, where one SONAR is the master, and you can add new audio and/or MIDI tracks on the slave that can be recorded to. The master would need to at least send pre-rendered versions of tracks to the slave to make sure the user on the slave can hear the full project (they need to be individual tracks to make sure mute/solo works correctly on both sides).
Kinda like Steinberg's
VST Connect Pro, but built into SONAR.
Or something.