I think TFA gets it all wrong. It's not that SQL databases do not scale per se, they just can't arbitrarily scale. Most applications today manage pretty well

I think TFA gets it all wrong. It's not that SQL databases do not scale per se, they just can't arbitrarily scale. Most applications today manage pretty well with nothing more than sharding and replication. Sure, it's not the optimal solution, and it's not easy - but it gets the job done. Facebook, at the very core (behind all the layers of cache), run, arguably, the largest MySQL landscape in the world - and they seem to be doing pretty good. Until Heroku comes up with a better solution (or a better question), TFA is no more than flamebait.