GOG's community wishlist contains crowdsourced suggestions for old games that players would love for them to revive, as well as features and more general requests. Among the entries currently being voted on are games like Diablo 2 and Black & White as well as less directly actionable suggestions like "Do not get bought by EA" and "Continue to be a DRM-free store, today, tomorrow, and forever!"
Still, no matter what kind of requests they are, it's impressive that GOG has ticked two million off their list. To celebrate that they're having a sale, with discounts on games that were added to the GOG library after being suggested by the community such as Grim Fandango and the first two WarCraft games.
Now let me know when they've got around to Silent Hill 2, Blade Runner, Discworld Noir, or Dark Omen.