This article confuses me . . . a better title would have been, "Why we changed languages, went from PaaS to IaaS, and changed our datastore - or why we changed everything". I find it interesting that the author didn't go from AppEngine to Heroku, which has robust NodeJS support, Memcache and Mongo support as well.

I applaud the author for making changes to support their business more effectively, I'm just not sure what I'm supposed to take away from this other than someone successfully changed some stuff.