Definitely agree that big, popular dating sites won't be quick to pick this up. I do see the possibility of them monitoring the usage of the API and perhaps integrating some 3rd party API's into their sites too.

What the dating API allows you to do is show off not only what you SAY you're doing, but what you're ACTUALLY doing. It adds an additional facet to someone's profile, which only enhances online dating in my opinion. Could be something larger players would want to look into.

The ongoing trend of mobile dating and social apps should benefit from this release.

There are plenty of startups struggling on the "chicken and egg" problem, starting with a 500k userbase is surely a good starting point. Of course big players won't contribute, it's built for their competitors, that's why this makes a lot of sense to me.