[kylecordes]

For PayPal to succeed it had to viciously hammer on a huge number of users who it algorithmically suspected might maybe be scammers. Blocking a tremendous amount of free activity in the process, punishing many innocent in addition to the guilty. This was done to create something that felt safe enough to get mainstream use.

That sounds somewhat like the Twitter of today, and not much like a hypothetical super-free-ified twitter.