I'm pretty surprised that Twitter is moving their homegrown stack to GCP. Twitter has a storied big data platform (Storm, Summingbird, Lambda Platform, Manhattan), and they have completely moved to the cloud. I wonder how the finances worked out; I'm sure Twitter paid a lot for their bespoke platform and Google must've been competitive. It was probably also easier as I imagine a lot of the engineers who considered those projects their children may have already moved on.