Not to be paranoid and cynical, but we don't actually know that Edward Snowden, personally, is still maintaining that account, even though the account was verified.
He's spoken publicly through video feeds at conferences etc. If he was being impersonated I'm fairly certain we would have heard about it by now.
Of course you could be cynical enough to say his video/voice etc is being faked as well, but you have to ground your beliefs somewhere and know there is a spoon when there is one...
