If you missed it on the news, a newspaper in New York has taken it upon themselves to publish an interactive map showing the names and addresses of all persons who legally own a gun in several New York counties.
This is wrong on so many levels that I don't even know where to start, but let me use it to illustrate one point: gun registration only seems harmless. I mentioned it briefly in my post about open carry. If you register your gun you have created a record. That record may be used by clever criminals, by government agents acting under color of law, or (as in this case) by idiot media hounds out to create a sensational news story and violate your privacy.
Gun registration was one of the first steps undertaken in the UK during their bid for gun control. After law abiding gun owners registered their guns, the British government used those same records to confiscate guns throughout the country.
Don't fall for it.