GM's patent starts with users creating an account for this service and saving their settings. According to the documentation, the info can include things like the seat and mirror positioning, radio presets, infotainment applications, and far more personal things like contacts, voicemail, and Internet history. When switching to a new vehicle, people could somehow authorize themselves and download all of that data via the wireless connection in the telematics system.
Obviously, with so much intimate data potentially available, security is vital. However, GM claims that a person's settings wouldn't be accessible by another user. The patent outlines many different ways this authorization could be given like a RFID chip, voice recognition, fingerprint analysis, or simply a text password. When no longer needed, the personal info is then removed from the vehicle.
While there's never a guarantee that patented technology actually makes production, it's easy to see the advantages of a system like this. GM outlines applications for car sharing services and rental companies in the documents. Although, this service might also be especially useful for couples to switch settings depending on who's driving.