If you've logged into Steam lately, you might notice a change in the overall scores for the games on the platform. Following through with updates that Steam officially posted yesterday, they have added a filtering system for users to find the reviews they want (by language, purchase type, and positive or negative reviews), but more importantly, a measure to prevent fake positive user reviews from being counted.
Steam admits that while the review score "has become a valuable shortcut for customers," it believes that it has "become a point of fixation for many developers are willing to employ deceptive tactics to generate a more positive review score."
Specifically, Steam curiously finds that reviews written based on games activated by Steam keys, which are free for developers to give out or sell, can be abnormally positive:
The majority of review score manipulation we're seeing by developers is through the process of giving out Steam keys to their game, which are then used to generate positive reviews. Some developers organize their own system using Steam keys on alternate accounts. Some organizations even offer paid services to write positive reviews.
As such, to prevent this artificial inflation of review score, user reviews made from Steam key activations will no longer count toward the score, though they can still be posted. But for abuse that is "clear and obvious, such as duplicated and/or generated reviews," Steam will be eliminating those reviews and eventually end their partnership with those developers whose deceptive practices continue.
That said, from what I can tell, developers can still purchase positive review scores if they flat-out pay users (or an organization that can handle this for them) money to get the game on Steam "legitimately" and then post the review from there. We'll see how
Steam is also looking into abuse with the "helpful" marking of reviews, with some groups of users marking certain reviews as helpful or unhelpful for the purpose of skewing perception. There's also the issue of people marking funny reviews as helpful and having titles with more "helpful" negative reviews but still having a positive rating.