Remember when Valve updated the Steam Subscriber Agreement in March to require that users disclose paid endorsements?
This week an example surfaced of how that can affect game developers, as Kotaku notes that Valve wiped all user reviews from the Steam page for Epic Quest of the 4 Crystals after the developers ran a promotion offering free copies of the game in exchange for said reviews.
This is important for game developers to know about because user reviews are prominently featured (in an aggregated form) on Steam's store listings, and thus getting your game's reviews wiped due to an error like this may affect your bottom line.
However, it's worth noting that at the time of this writing the affected game's Steam page has been repopulated with over 70 user reviews, most of them positive.
Valve sent copies of each of the game's user reviews to their respective authors before it wiped them from Steam, and it seems at least some of them have reposted their original reviews with an added disclaimer about their participation in the developer's promotion.