How a Bad PHP Code Led to Google’s Dodgeball and the Birth of Foursquare

In 2005 Dennis arrived at Google's New York office for an interview, where he struggled with classic algorithm questions and shocked interviewers with terrible PHP code.

Despite his lack of formal programming training, Google hired him to acquire the website he had built, called Dodgeball, to capture its revenue.

Dennis had earlier conceived the idea of a location‑based service while sending SMS messages to a server, allowing friends to see each other's positions on a web page.

After a difficult period working at various companies and a stint teaching ski lessons, he enrolled in NYU’s Interactive Telecommunications Program, where he and Renate rewrote the Dodgeball system in PHP for his master’s project.

In 2004 they launched Dodgeball, which quickly gained users, media attention, and eventually attracted Google’s acquisition.

Google’s purchase did not provide the support Dennis expected, and the service was later shut down in 2009, giving way to Google Latitude.

Undeterred, Dennis and Renate created a new version of the service, initially called Jimmy Disco, which became the wildly successful Foursquare, growing to millions of users and even attracting President Obama.

Throughout the journey, Dennis’s coding skills remained modest, but his innovative ideas proved that a compelling concept can thrive even with imperfect code.