The Infrastructure Behind Twitter: Scale
100,000's of servers for 
100,000,000 of messages/day ?I understand that half the servers aren't even doing messages, but, isn't WhatsApp doing 2 orders of magnitude more messages with 3 orders of magnitude (?) fewer servers?Is that right?  I'm curious how one would justify 10,000X worse?So for each message, 10,000X more equipment is needed?