Excellent information, and a little surprising. But I have never given my real phone number out to a dancer/escort etc. I use a separate loadable phone I got at the grocery store for that. No real names and untraceable as to my identity, at least that's the plan, but in this day and age, perhaps anything is possible.
I saw an app the other day that can GPS any photo you download onto the Internet, even if it is taken of something as generic as the dash board of your car. It recognizes the kind of camera/phone/aper setting/ and location, and will Google earth the location down to a few feet.
My cousin asked me to join 'linkedin' and post a profile. I did, but was careful to keep information about myself generic. Linkedin will link individual profiles to like minded professionals. A neighbor who lives down the street and with whom I have only communicated with once by email, and only met once, popped up in my computer as 'someone I might know'. It gave her full real profile and all personal information about her and her business, and all her contacts. Certainly information that I wouldn't want my neighbors to know about me. I would imagine that linkedin is data mining. But not sure.
I guess the lesson is that, nothing is really private anymore. Can you say "1984"