I've been thinking about my net.footprint a bit recently. I have a listed phone number and a 750-entry Google footprint under my real name. And that real name is not exactly a secret; even people who meet me as 'phi' can map that to 'Nicholas Shectman' with an obvious Google search. This is all fine. But spammers make me a bit more possessive with my main email address; my theory is that an actual human will be able to figure it out by finding my real home page (it's in my userinfo, and findable by the dedicated without that) and reasoning that since its URL is of the form http://$DOMAIN/~$USER, my address might be $USER@$DOMAIN.
So far so good, and so I feel I should not be surprised if people I meet take a similar kind of care.
But the application of this practice in the other direction is a little discomfiting. I can take someone's nickname/alias and a scrap of context and have their home address within seconds. Half an hour later I still don't have an email address. And yet using the email address, if I eventually find it, seems like less of an invasion of privacy if I'd like to actually get in touch. What's up with that?