Mr. Snowden made his debut today on Twitter with the @Snowden handle (lucky it was still available). At press time, he was only following a single entity: the NSA, and had already attracted 227K followers.
He describes himself thusly: "I used to work for the government. Now I work for the public. Director at @FreedomofPress."
According to Wired, he is using the photo shot for the magazine's 2014 cover story on Snowden.