Twitter? Really? If you judge by the stuff they put out publicly it’s mostly google and fb. Even linkedin has kafka. What did twitter ever put out? Mesos? (No, thanks)
I wasn't judging by open source. I was judging by:
1) Who is hiring top people in my group of colleagues
2) Who is described by people who work there as having a healthy work environment (i.e. people want to work there)
For Twitter, I'll admit I have a small enough N that I can't speak with very much confidence at all. I have one or two friends there, but they seem very happy, describe their peers as smart, etc. They're competent and I trust them, but well, one or two anecdotes doesn't make data.
But Twitter did put out a few high-profile things like Bootstrap. I don't like or use Bootstrap myself, but it's predominant in that area.
