When ever a person is posting about a website on a forum it can eithier be becoause of one of many different reason these include
-SEO the webmaster of the forum is trying to create backlinks to his own website to increase their own search ranking
-People trying to get refferals, many gpt websites have refferal systems where by people are able to earn a percentage of all members earnings that have signed up through their refferal link. It is important to understand that these people might have never actually been payed by the website before and are just trying to see if they can get referrals, it is quite easy also to get fake payment proof from google.
-The webmaster could be pretending to be someone who has been payed and is trying to trick people into signing up. They can also then make multiple accounts on the same forum to then backup their post even more.
You cannot always trust people who are promoting websites!