Dennis is a Researcher in Microsoft Research's Silicon Valley lab, which he joined in May, 2003. His research interests include a wide variety of topics including web crawling, the evolution and similarity of pages on the web, identifying spam web pages, and large scale distributed systems. He is currently working on DryadLINQ, TidyFS, and a project evaluating policies for corpus selection. Interesting past projects include the MSRBot web crawler, Dryad, the Your Desktop on Your Keychain project, which utilizes flash memory devices to enable users to carry their desktop PC state with them from machine to machine, and PageTurner, a large scale study of the evolution of web-pages.