While on the Frontend Framework team, I got promoted to Principal Engineer, which has the following responsibilities on top of Senior Engineer:
* serve as a reference point to the rest of the engineers on the company, regarding our internal structure, code, tools and processes
* serve as a "walking documentation" for our technical development
Some achievements that led to this promotion:
Assisting many product teams achieve their goals by joining them temporarily and bringing the tools and processes of our team to theirs, while developing consumer-facing products (new albums, profile redesign...)
Using bleeding edge web technologies, like DOM Mutation Observers, and CSP to fight 3rd party adware inserted on our platform by infected computers (clean navigation).
Lightning talk on an international JS conference about Promises (dotJS, Paris, December 2012)
Many internal talks and trainings regarding JS (both basic and advanced) so the level of the JS code written in the company may increase.