How would you design the twitter timeline?

#design #architecture #tutorial #codenewbie

A formidable design problem

All of us use/have used twitter at some point of time in our lives. Part of the reason why Twitter is successful, I believe is because the concept is so simple at its core:

phrase your idea in 280 characters or less and then with the press of a button, broadcast it to the world.
And then, whenever someone who follows you logs in, they will get to see that tweet in their timeline.

But have you ever imagined the logistics behind implementing this simple concept? What would happen when people with millions & millions of followers send out a tweet and each of their followers expects that tweet to appear in their timeline in real-time?

I created this video which was originally based on this talk by Raffi Krikorian who was a senior director at twitter at that time. Although the talk is quite old, it gives us an insight into how designing anything should be approached at the scale of Twitter.