Lol, people keep taking about Uber building internal products because 3rd party stuff can't "Uber" scale, I think the real drive to build internal apps is to save on licensing costs.

Take chat, hipcat is like 5-10 bucks per month per user. Uber has about 20k FTEs, 40k contractors all use chat. That's 3 to 600k per month just on chat.

Don't forget scale is expensive.

I can't imagine how much that many slack licenses would cost.