This summer, a dating site I helped to found, OkCupid, announced that it had tested the effectiveness of its matching algorithm on a small number of users. We run tests on the site all the time, and we were particularly careful with this one because we were tinkering with something fundamental to the user experience. The test was brief, and everyone affected was made aware of it soon afterward.

But the reaction to our test was explosive, largely negative and, in retrospect, understandable given the way we presented the results....