Dating by algorithm

In this post NYTimes science reporter John Tierney, who writes the blog Tierny Lab, does a little experiment on the dating site eHarmony. eHarmony uses a complicated algorithm to match couples based on a lengthy personality questionnaire. Tierney seems surprised that the algorithm doesn't match him up with his wife, even when restricted geographically to his NYC zip code and even after further tweaking of their survey responses and consultation with eHarmony's chief scientist.

What Tierney doesn't seem to understand is that, under almost any algorithm for matching (including the "correct" algorithm that would predict happiness in his case), it is highly unlikely that the wife he found is actually optimal :-) Within a 10 mile radius (in NYC) there are dozens (hundreds? thousands?) of better matches he unfortunately never met. It's unromantic but true that chance played a bigger role in his marriage choice than optimality.

On a related note, I wonder whether social networking and online dating are gradually increasing the overall quality of marriages. It seems much easier to meet compatible partners than it was in the pre-Internet dark ages.