Simon is a Principle Engineer specializing in machine learning and artificial intelligence. He has made foundational contributions to Google's Web Search ranking, was a member of the small team that built the original AdSense prototype and production system, and he co-created the first broadly used large-scale machine learning system at Google.
Simon has applied machine learning to many areas across Google. For example, he co-created Gmail's original spam filter, built the original machine learning system that decided what to display on Google's search page beyond the regular ten-blue-links, co-designed the blue and red underline system in Docs, Gmail and Android, and has co-designed multiple systems that each increased revenue by a few to several percent.
More recently, Simon helped design large language model pre-training datasets, co-designed Gemini components that improved Google Search AI overviews and AI mode, and is exploring the extent to which LLMs are aware of their internal thought processes.