The video era
Between roughly 2009 and 2014, Cutts published hundreds of short answer videos. They were shot plainly, deliberately unhyped, and answered specific questions from webmasters. They effectively established the boundary of what Google considered acceptable optimisation — no paid links passing PageRank, no doorway pages, no cloaking, no keyword-stuffed anchor text. Those boundaries are still the baseline.
Technical footprint
He designed Google's SafeSearch filter and is a named co-inventor on multiple patents relating to web spam detection. The Penguin and Panda enforcement eras happened under his team's watch and permanently reshaped the link economy.