I used to work at HomeStars. Set up over 400 businesses. I'd say it works for about 50% of contractors. My guys that got reviews, were professionals, and did good work, made a killing, 10x more than what they were paying us. The guys that got 1, 2, 3 reviews, expected to gifted a 100k basement reno the day they signed up, those guys, just don't get how business works. Same guys, were late to quotes, responded to leads days later, those guys sucked. You're seeing a lot of those people in these comments. Running here leaving a bad review because, really, they're not good contractors. Biggest mistake a contractor can make is also getting started on the cheapest price - it would be like if a homeowner said "do this basement renovation for 25k" - but you knew it was a 75k job - if you want leads, you have to pay. All these comments saying " Oh I paid $250, $400, got nothing, it's a scam" what do you expect? My guys who paid $800-$1000+ a month, got tons of leads, closed a ton of work, never cancelled.
I'm a homeowner now, use HomeStars often to find a reputable contractor. My advise from someone who actually knows how this works, don't listen to the people below: Cheap, and bad at what they do.