When you pay someone to post on your site it's bad.
First they are joining just to get money. That don't give 2 shits about your content or anything. Once they reach your goal for them they are gone never to return. it's doesn't happen in all cases but it's a high chance it will.
Also the user could just be posting all this LQ shit everywhere. People will get annoyed by this user and maybe even leave the site. It's just not worth it. Have your members recruit there friends and then it will grow.
Lastly the user will just spam and post in every thread and make new ones every 5 seconds. When I became re-active on MF I had about 100+ Post per day. it made me look like a little bitch spammer and it made staff look bad because they did nothing to stop it.
So if you want to have a nice looking site just recruit some of your friends and give prizes for legit referrals. Thanks for reading my rant.