[mcsoft]

The article says nothing about how they instantaneously updated millions of user feeds. It was the most challenging task, as it's way easier to scale reads than writes in distributed systems. Rumor has it early Twitter had a target of 5 sec to update everyone of 50M fan feeds when Justin Bieber touched a screen. I would love to hear some technical details on how they did it.

[pnt12]

I remember reading a case study from their engineering blog about this a few years ago - I couldn't quickly find it but maybe it's still out there. It was some think about optimizing for read speed, because one write from a celebrity would cause thousands or millions of reads.