Bitcoin is the currency of the Internet: a distributed, worldwide, decentralized digital money. Unlike traditional currencies such as dollars, bitcoins are issued and managed without any central authority whatsoever: there is no government, company, or bank in charge of Bitcoin. As such, it is more resistant to wild inflation and corrupt banks.
Thiel occasionally says some smart things that I can get behind, but most of the time he's just a worse doomsday profiteer than Alex Jones.