Foursquare: Today's best-executing startup - Anil Dash
A position I agree with though was not fully on the bandwagon until I experienced the execution of Small Business Saturday. Also of note is foursquare migrated their technology to Scala (from PHP?), and did so in a way that was largely transparent to their user base. I’ve been impressed with them even when I was pessimistic (which was due to a not yet realized business model). 4sq is an impressive organization.
