I haven't read the article, but I'm guessing this is probably a typical 2-way match algorithm, or else it really doesn't make sense. i.e., both friends have to put the other in their "secret crush" list for it to inform them that they have a crush on each other.

What they really need is a "secret crush for FWB only" list: what if I have a friend that I'd be happy to be FWB with, but have zero interest in a serious relationship, but don't want to broach that topic with her for fear that it would mess up our friendship? This would be a perfect use for FB.