Rudder was a founder of OkCupid. In the years immediately following the site's creation, he worked on the front-end product and developed the site's editorial voice.

From 2009 - 2011, OkCupid published statistical observations and analysis of members' preferences and connections; the blog posts were written by Rudder and gained wide-spread media attention. In February 2011, OkCupid was sold to IAC, the owner of Match.com and other dating properties, for $90 million.