I can see this going similar way like the useless do not call list.
The legit companies that are operating in California getting clean and the scummy companies operating outside holding all the data and having a ball with them
If your data is available to the public, people can also learn your behaviour, likes and dislikes.
From that information
Authorities can coerce you to do something you do not want to do (like make a false claim) because if you don't they can use your dislikes and deny your likes to make you suffer until you relent
Advertisers can push advertisements of things you like and make you spend a lot more
Thieves will know when is the most likely time that you and your family be at home and break in during those times
It's easier to kill the terrorists in the hospitals when the hospitals are more flammable...