Steam users are now required to disclose if they receive payment to endorse products through the Steam Curators List or the Steam Broadcasting service, according to an update to the Steam subscriber agreement released by Valve today.

"If you use Steam services (e.g. the Steam Curators' Lists or the Steam Broadcasting service) to promote or endorse a product, service or event in return for any kind of consideration from a third party (including non-monetary rewards such as free games), you must clearly indicate the source of such consideration to your audience," the new subscriber agreement states.

Valve introduced its Curator system last year, allowing Steam users to follow curators who recommend and review titles on the service. Curators are listed on the Steam home page and individual product pages, which is where Valve suggests users look to find curators who match their tastes.

In order to become a curator, a user (or a collection of users) needs to either start a new Steam Community group or be an officer/moderator of a group. Once that's done, users will need to make at least 10 recommendations on Steam. Curators can link to websites, YouTube videos, podcasts, tweets and more to flesh out their recommendations, and Valve says anyone can take part — developers, journalists, artists, critics, etc. Top curators are highlighted based on how many followers they have on Steam, though that may change over time.

Indie developers have said they've already felt the benefit.

However, problems have arisen more recently due to a lack of public disclosure on the digital platform. Earlier this year, Valve asked developers with games listed on Steam Greenlight to stop trading game keys for votes, saying it puts them "in a really uncomfortable position.

"We do not think these votes accurate reflect customer interest," Valve said in a message at the time, "and it makes our job harder in deciding which games customers would actually buy and play on Steam."