I have also observed that TripAdvisor seems to have rather poor fraud control on their reviews.
Recently I was driving home after cutting a trip short due to health issues, and then to compound difficulties, my car was overheating. I asked my girlfriend to help me find a motel - I knew of one on the way back to town, about 20 miles closer, and requested she look up reviews online. She told me the one I was thinking of looked fine, and had several positive reviews online. One even said “the best part about our trip to Colorado”, she quoted as I parked and walked inside.
It turned out to be decidely not the best part about anything in Colorado, unless you are a Satanist who pairs a fondness for shabby 70s decor with an aversion to cleanliness. I had already paid when I fully realized this, and only spent 25 minutes at the hotel before I essentially fled in terror.
When researching how this could have happened, I found that Yelp gave this motel only 1.5 stars, and had several reviews with similar stories, noting things like how the clerk seemed to be on drugs and was wearing a large pentagram necklace. This man looked somewhat like an elderly mixture of Frank Zappa and Bowie with anorexia, and insisted on walking me to my room for reasons unknown. I was not provided with a key, and the room had no way to lock from the inside.
Google has mixed reviews for them, with some likely fakes standing out and also reviews sourced from TripAdvisor. The TripAdvisor reviews are mixed as well, with many glowing 5 stars reviews balanced by many 1 stars for a total of 3 stars. Many of the 5 star reviews are defensive about the specifics of other negative reviews.
I looked into this motel on FB, and found it had the highest rating there - 4.4 stars. Not a trace of anything negative. I was also able to find the personal page of the man I talked to, who was cited as seemingly drug-addled and pentagram-adorned in other reviews as well as my experience. His page mentioned how his partner, owner of the motel, promoted him from clerk to manager on their 30th anniversary as a couple. He had many pictures of their satanic altars, references to demons, the pitbulls (referred to negatively in reviews) being ‘possessed’, and pictures around the motel. I feel somewhat lucky to have escaped.
So, in summary, Yelp had the most accurate reviews and presented the most realistic picture. Facebook presented the motel as they would like to be seen. Google and TripAdvisor are in between, showing equal amounts of true and false reviews.