More seriously, he made a large number of enormous mistakes, here are the biggest:
1. Looks like his real name was on the goddamn hosting for KAT. Perfect job for an anonymous shell company held by a Russian lawyer, but instead he left a business card on a neat little stand at the crime scene.
2. Not separating his real name completely from his identity as KAT admin OR his casual pseudonym. He should've created a completely new identity for the KAT admin that doesn't touch any others with a 30-foot pole.
3. Apparently he thought Canada was a good place to host the servers safe from the reach of US lawmen. Such a US-unfriendly place this is, that he felt confident storing incriminating info on the server for some reason.
4. Insufficient money laundering. He even could've accepted ad payments in Bitcoin. Really, he put less effort into laundering criminal proceeds than your average 1%er puts into not paying taxes.
5. Being on Facebook never helps.
In short, he was running this operation almost completely in the open, relying only on the assumption that he couldn't be extradited and the obfuscation of naming the company Cryptoneat instead of KickassTorrents Inc. to keep his ass out of prison. Ross "You'll take payment in Bitcoin without a second thought, Mr. Mob Boss? Seems Legit." Ulbricht looks like a genius in comparison.