I don't think there's a huge differences serving 1 million daily users or serving 100 million. In both cases you need highly scaleable systems. In 100 million c

I don't think there's a huge differences serving 1 million daily users or serving 100 million. In both cases you need highly scaleable systems. In 100 million case you need a lot more computers, but I think the overall structure of the systems could be very similar (e.g. sharded databases, auto fail-overs, extensive monitoring etc.) Of course you need a larger team serving 100million users, but I don't think you need to scale the team as much as Twitter has done.