Steam is a great example. If you click through to the person who made the review, you can also look at other games they own or other things they reviewed to get a sense the kind of person they are. If they're like you, then their review is probably going to be more helpful to you. If they're very much NOT like you, then that's a useful data point too.
I think one of the special challenges with Glassdoor is that reviewers are anonymous, in order to protect them from career-related backlash. This makes it harder to understand if a particular reviewer's experience is something that will also affect you. But if you think about it, that is a real indictment of the state of workplace relations - workers are at such a structural disadvantage that they are terrified of sharing candid views about current or even former employers in a way that could come back to bite them.
I know i've gone out of my way to try to avoid putting identifying information into Glassdoor, and even toned down some criticism as insurance just in case the employer did figure out who i was. That's not a good thing - it only serves to make my review less helpful! This is all the more reason why it's so disappointing to me that Glassdoor has openly shifted to be a service focused on corporate branding - employers already had all the power to start with.
Steam reviews are interesting because I have started watching someone’s YouTube lets play instead. Even bad ones are mildly interesting and they quickly tell you a lot more about the game than what I get from random reviews.
The best online review system for me is Rotten Tomatoes which shows both what the general public thinks and what the critics do. Looking at say https://www.rottentomatoes.com/m/star_wars_the_rise_of_skywa... I appreciate many of the viewers liked it, but it’s the critics that I find actually agree with. Yep, worse than the prequels, but not quite walk out of the movie theater bad. https://www.rottentomatoes.com/m/star_wars_episode_i_the_pha..., https://www.rottentomatoes.com/m/star_wars_episode_ii_attack..., or https://www.rottentomatoes.com/m/star_wars_episode_iii_reven...
What is a problem is just presenting an average of the ratings, though.
A 1 star review because it was DOA says nothing about failure rates. People also have different preferences on things like cost, spicy food, or what looks tacky making a 3 vs 4 star review mostly meaningless.
This is why independent reviews like consumer reports are so useful. Look at a comparison between similar devices and consider tradeoffs. Or find a movie reviewer with similar tastes and you can generally just follow their suggestions.
Net result reviewers and rating systems just don’t have great incentives which devolves into companies just gaming the algorithm.