[mryan]

I read that Netflix encodes each video 100+ times to ensure good performance across a wide range of devices. In addition to the "social network" side of the site (recommendations, what your friends watch, etc.) there is a lot of processing going on in the background.

[rogerbinns]

I vaguely recall the number being encoded 120 different ways. In any event this is independent of the number of users, and proportional to the amount of new incoming content. It also isn't real time, and doesn't really matter how long it takes other than marketing deadlines when they announce a new season of something far in advance.

The recommendations don't show any evidence of being calculated frequently, nor do they have to be done in real time. There is certainly way less appearing to go on than a site like Reddit.

"There is a lot of processing going on in the background" doesn't really answer the question :-)

[mryan]

Sure, this processing does not need to happen in real time, but it does need to happen.

My point was that to assume the user-visible portion of the site accounts for most of their computing needs is probably incorrect. Video encoding was just one of the first things I thought of, and I bet there are many more.

I admit "processing going on in the background" was a real hand-wavey way to phrase it, but I think you know what I mean. It's an iceberg - there's a lot happening under the surface. :-)