Heres a link to a forbes article on the subject

https://www.forbes.com/sites/jaymcgregor/2017/02/20/reddit-is-being-manipulated-by-big-financial-services-companies/

And here is a guide to fourm spies and shills

http://www.abovetopsecret.com/forum/thread1195748/pg1

Both inteteresting reads and good places to start