As the site has been growing, I feel like there are increasesd amounts of astroturfing going on. Maybe I'm being overly paranoid, or maybe I've visited r/hailcorporate too many times. However, consider this - reddit is a huge website with a lot of reach, where it's free to post. Even better than that, you can control discussions if you're a moderator. This means you can advertise comparatively cheaply, in a way that looks genuine and reach a wide, desirable audience with your message.
Would you be surprised if there are whole businesses that specialise in creating positive content about brands on reddit? I would be shocked if there weren't.