Google always surprises users with new add on to it’s existing products.
“Feather” Beta is an opt-in beta for “Feather” support on YouTube. The “Feather” project is intended to serve YouTube video watch pages with the lowest latency possible. It achieves this by severely limiting the features available to the viewer and making use of advanced web techniques for reducing the total amount of bytes downloaded by the browser. It is a work in progress and may not work for all videos.
You can join the beta project here.