We’d worry about making our diaries public because that would tell everyone what we think. We’re less clear about the implications of letting strangers collect information about what we want, what we like, what we buy, and what we habitually do late at night when we’re tired.

Teresa Nielsen Hayden at Making Light

From a comment in discussion:

I, like much of my generation, don’t actually expect privacy anymore. We understand gaming the algorithm so that the information we would like to bury gets buried behind a wealth of other links and information, too deep to find casually.

ETA, though not entirely the same idea (this one you should definitely go read):

Standing at the front desk of a restaurant on the phone with a complete stranger was the absolute last thing I expected from a harmless tweet about meeting friends from the internet and a link to my location.