Facebook can go real big here. The have ridiculous distribution (2B+ monthly users). If they roll out a crypto payment or stored value system to their users, the network effects / lock in will be insane. Only Google could really compete (Amazon doesn't have the same international presence as Facebook or Google; Microsoft doesn't have enough mobile presence; Apple only has rich users).

The question is will Facebook take this seriously and invest over the long term to win. Historically, they've had a terrible history of investing and committing to new efforts that don't pay out immediately (killing Parse, sunsetting big parts of their platform, shutting down their Creative Labs, etc.)

Well let's see