someone know how steam decides which games will go on sale?

some questions will never be answered

I imagine the developers/publishers decide.

Magic 8 ball.

:-D

They play Spin the Gaben.

If some games aren't on sales is because gabe ate them..

If the devs refuse to go on sale, the games don't.

I choose which games go on sale. No Arma II flash sale for you! MUAHAHAHAH

I'm still waitinf for a KoA:R sale, but sadly it won't happen

Gaben throws darts at a list of every game on Steam and the ones they hit go on sale.

Unlike indie bundles usually the developer + valve determine what percentages off for a particular game.

So for instance they may request 33% off with 50% off as a daily or 20% off with 25% off max in the next 2 months