Twitter puts out a LOT of software, and open-sources a good portion. I don't know if this is smart in the sense of being overstaffed relative to their revenue, but they do it regardless. Some examples:

[1] Fabric, an SDK for mobile apps - https://docs.fabric.io/android/fabric/overview.html

[2] Heron, a realtime, distributed, fault-tolerant stream processing engine - https://github.com/twitter/heron

[3] Finagle, a fault tolerant, protocol-agnostic RPC system - https://github.com/twitter/finagle/

[4] FlockDB, a distributed, fault-tolerant graph database - https://github.com/twitter/flockdb

[5] Ruby implementation of the ICU (International Components for Unicode - https://github.com/twitter/twitter-cldr-rb

[6] Clockwork Raven, Human-Powered Data Analysis with Mechanical Turk - https://github.com/twitter/clockworkraven

[7] Gizzard, a flexible sharding framework for creating eventually-consistent distributed datastores - https://github.com/twitter/gizzard

[8] Twemcache, a Twitter fork of Memcached - https://github.com/twitter/twemcache

[9] Twemproxy, a fast, light-weight proxy for memcached and redis - https://github.com/twitter/twemproxy

[10] Iago, a webapp load tester - https://github.com/twitter/iago

[11] Ospriet, a bestof/voting app - https://github.com/twitter/ospriet

Thanks, I wasn't familiar with many of these projects. I'm still not sure whether all this output justifies the staff, or whether they're over-engineering the hell out of a microblogging service.

I think Fabric does "help" their revenue ID'ing all those phones where Fabric-enabled apps are installed.

Great list! At some point, I think this would have included Bootstrap as well?

> What do the bulk of these engineers work on, day to day?

Not the Mac app that's for sure.