It recently came to light that an update to the Steamworks Community FAQ forbids developers from using Steam's Community Hub to promote non-Steam versions of their games. It's not something that happens a lot, but it does happen, especially with the advent of the Epic Games Store: As we noted in December 2018, for instance, Unknown Worlds was using the Subnautica Steam page to support the game (and thus, arguably, promote it) on the Epic Games Store, because EGS doesn't have forums.
The FAQ would seem to close the door on that sort of activity in the future. "In the game you ship via Steam, and in communications on Steam, you may only promote the Steam version and its availability via Steam, and not other distribution outlets," it says. "This applies both to full versions of your game and to content patches that change the existing version."
The language is broad, and some users read it as forbidding not just announcements of releases and updates on other storefronts, but also things like unofficial patches released off of Steam. Today, however, Valve issued a statement clarifying that the policy isn't actually new at all, and that the FAQ was updated simply to ensure that developers are fully informed.
"Regarding the updated language on the Steamworks Community FAQ; the general spirit of this update was to remind content creators that their Steam pages should not be used for certain activities such as for the promotion of a game’s exclusive availability on a competing platform, the promotion of an external download that circumvents Steam content policies, or the promotion of other activity that conflicts with the Steam Distribution Agreement," Valve said.
"The new language on the FAQ was not really the introduction of any new policy or policing that should concern the majority of those publishing on Steam, but more of a reminder of existing rules for a small number of developers exploring the boundaries of the existing policies."
So while the codification of that rule into the FAQ is relatively new—a rep said separately that it was actually updated a couple of months ago—it doesn't sound like Steam itself will be dramatically impacted. The rep also said that in cases where developers were found to be in violation of the policy, "we deal with each issue on a case by case basis and communicate with the content creator in an attempt to resolve whatever the issue may be."