Given that all of this tech is already being used inside Twitter, I feel it is unethical to discuss any non-public info (like discussions with cloud vendors on cost etc.) in public. The engineers have been kicked out, the tech still belongs to Twitter. This is not "decimation" of the engineering, just of engineers' egos. Someone else will do the job, the show will go on.
Many of the projects mentioned there are open source and have been known publicly for a while, and talks about them have been presented over the years in many conferences.
