[Twisell]

Ok, so maybe we are talking about the same field of science, but it seems that, from what they say there is two very distinct approach.

1.Collect personal data, send them to mainframe, use them to profile and deliver custom tailored services. When sharing hash so that individual records can't be extrapolated

2.Collect personal data, use them locally sometimes using mainframe provided 'models'. Return to mainframe hashed records to improve models.

Google is clearly using 1. while Apple claim to target 2. (I don't think it's actually the case now because I though Siri actually store some personal data on the cloud so far)