During my time maintaining the LinkedIn Desktop feed, I was “loaned” to the Messaging team to help build the new messaging experience on mobile web. I joined 2 other folks to help work on this product (Sponsored InMail, Share as Message from Feed, etc.).
This was a fast-paced environment, and I learned a lot about Ember 2.0. Developing for mobile-web was also quite interesting for me because performance is limited (network latency, slower cpu) and layout is a lot more variable (lots more variation in screen sizes) than desktop.