He exposed his email address containing his name as a contact email for silkroad business, so he pretty much gave himself in. With that kind of "attention to details", I wouldn't be surprised if he even had misconfigured TOR.
Not exactly. He exposed his email address as a contact for bitcoin related development, then used the same username some time later as one of the first people to _discuss_ silk road. It's a tenuous connection at best, but this seemingly minor opsec lapse gave the investigators a hint to follow.
