If you remember the old OkCupid blog they used to post interesting articles about online dating. I know their article about whether you should smile on your profile picture was eventually debunked [1], but it was nonetheless nice to have objective, data-based, non-pua advice on how to be successful in online dating.
There was an actual effort at data science going on here before the marketing team took it over in the latter years. See the published book Dataclysm by one of the founders for more of the good stuff.
[1] https://blog.photofeeler.com/okcupid-is-wrong-about-smiling-...