Here comes the algorithm - Valve updating Steam to show different games for discounts and events
(www.gamingonlinux.com)
It may have skew for bigname game users, but for somebody that has random tastes its done a decent job at showing me games.
I.e. I mainly play Mudrunner/Snowrunner, MechWarrior 5 Mercs, and Wingspan. Steam showed me a single mission indie shooter that cost $1. I enjoyed it. Very limited replay value. And Beacon Patrol...which I also enjoyed.