I think there are some things left out of this video, but he gives a fairly good summary of the concept: https://www.youtube.com/watch?v=UsLkGWTCjQI

I'm not quite as cynical about smaller publications as he is and haven't always found that there's much predictaibility to which pieces will succeed and which won't. But with the boost sytem they've had in place lately, I think the difference they make can sometimes be instrumental. If there are any more specific questions you have, just let me know!