We’re being watched…mostly by each other and a few spammers.
I think it is just as “safe” to be completely open as to be completely closed. The more of our information out there, the less it actually means, because we are humans that can alter our behaviour unexpectedly. For example, I’ve never been interested in the stupid books and CDs that Amazon throws at me based on their view of my interests.
The benefits of being “open” are great. We get weirdos emailing us with crazy product ideas, students, other Porsche enthusiasts (even if I don’t like a Porsche made after 1999), etc.