[StephenAmar]

+1 the comparisons are not great. How much engineer-hours did it take to build Rama itself?

The numbers they got for Twitter likely include the time it took to build their infrastructure, common libraries (like finagle,…)

[jacoblambda]

Honestly I'm willing to accept the number they gave since the author (Nathan Marz) was one of the lead/founding devs for twitter's streaming compute backend in the past.

[paxys]

Don't forget their entire ads system, data processing/analytics, monitoring, customer support, payments, internationalization. They have replicated at most a tiny bit of Twitter's core infra for sending Tweets. The company itself does a lot more than that.