The Washington Wire Blog at wsj.com relays an announcement made by Mayor Bloomberg:
I have filed papers with the New York City Board of Elections to change my status as a voter and register as unaffiliated with any political party. Although my plans for the future haven’t changed, I believe this brings my affiliation into alignment with how I have led and will continue to lead our City.
Of course, folks are speculating whether this is yet another sign that Bloomberg might be running despite his vehement denials to the contrary.