Does anyone remember that angry email they sent 5 years ago where they were criticizing their boss? Google does. What kind of profile can you build from thousands and thousands of such emails, messages and queries, and location data and pictures, videos, actions on social networks?
I think some companies have a better idea about who some people are than those people themselves.
Good companies use information they collect to provide better services. Bad companies use it to rip people off. The problem of bad companies doing bad things is independent of companies having information about people.