The internet thing it mentions is for the lame MyAir crap. Don't bother registering unless you want some rather sophomoric reinforcement about how you are doing. They award points for how long you use the machine and how well controlled the leaks are and how low the AHI and they ding you points if you turn the machine off and back on during the night but the bulk of the score is hours of use and on/off dings.
Personally I don't need MyAir telling me I had a score of 90 last night and got dinged because I got up to deal with a barking dog.
I already know about how I slept and feel when I don't get enough sleep.

Some people like it though. They like the reinforcement that things are going well and getting an email telling them the score or a note on an app on their phone. That's fine for those people. Just not my thing.
You don't get in in depth evaluation of your nightly data. ResMed assumes the doctor is doing that. It won't tell you anything except maybe you need to see your doctor.
I never bothered registering any of my AirSense/Air Curve machines so it might be sending data somewhere but I don't care because they have no idea I have these machines since they were all bought privately and I haven't bothered to register them.
There is an airplane mode available to stop any transmissions but I haven't bothered with it because again...no one knows that I have the machine. The data that is transmitted is tied to a machine serial number and if they don't know who is using that serial number it's useless data.