To my mind the big news is Turbolink, A simple tech to build SPA with the following roots : - the robustness & ecosystem of the rails server side (great testing stack & battle tested backend) - the lightweight approach of rails/javascript, which is opting out of jquery : meaning that SPAs won't have to include jQuery and the whole JS world (client side speed will be greatly enhanced) - the overall simplicity (no huge javascript stack pilling angular, react, redux, flux, webpack etc...).

That's rad.