> The discussion continued to talk about tort law, and how he's unable to even get a person to sue. He can't sue Yelp, because Yelp wasn't the author of those p

> The discussion continued to talk about tort law, and how he's unable to even get a person to sue. He can't sue Yelp, because Yelp wasn't the author of those posts. Yelp doesn't need to be a party to the lawsuit for a subpoena to be issued to them. You sue the poster as John Doe, send a subpoena to Yelp for the poster's account information and IP address, send a subpoena to the poster's ISP for the account information of the user assigned that IP address at that time, and keep following that trail. Eventually you might find some person who was paid to post the fake reviews, and you can use the legal system to find out who paid them. (In fact, they'll probably cooperate with your investigation in exchange for dropping them as a party.) There's no guarantee of success -- you might find the trail ends up with a no-logging VPN, an open Wi-Fi hotspot, or some other multi-user shared environment where the activity can't be linked to a specific person -- but it is possible to try.