I've known the Holloway team almost since inception, and knew Josh (one of the cofounders) from before that. I had originally cold reached out to him on LinkedIn after I read some stuff he had written on Quora (where I was working at the time), and we got coffee a few times and became friends.
I've been a huge fan of what they're trying to do. It's also a really strong team—they're polymaths in some sort. They had wanted to write about hiring and recruiting (and in fact had already started having conversations about it with some really credible folk), and at some point we just decided I'd help out (I had written some stuff on Quora and Medium but never worked on something of this magnitude).
Anyway that's probably more detail than you wanted :) I'd say reach out from their website (or by emailing contributing@h..y.com), they're pretty approachable (Andy is in these threads too).
Just curious...how did you start working with Holloway? Did you reach out to them or did they find you?