People keep repeating the refrain of Google/Facebook selling your data, but is there any evidence of a single case where this actually happened? They use your data, to let advertisers target specific subgroups of the population. The companies that you should be concerned about selling your data aren't the advertising companies, they're the financial companies that are literally selling your transaction data to those and other companies.

I think it's a rather common dysphemism used in context of targeted advertising. Monetizing user data—while not actually selling the data (in the literal sense of the term)—is considered by many to constitute having their data sold, albeit with a layer of indirection.

My understanding is that while this is certainly superior to your data being actually sold, privacy is nonetheless adversely affected in fairly significant ways.