You can optimize on multiple fronts. Just because facebook needs to scale data access doesn't mean it shouldn't scale processing time too. As the post mentioned

You can optimize on multiple fronts. Just because facebook needs to scale data access doesn't mean it shouldn't scale processing time too. As the post mentioned, this has had a huge impact. [i work at facebook, comments on this site are my own opinion, and I'm not intimately involved in the project] But generally I agree about new projects. If you have a favorite language, use it.