Well using forums is not a bad idea, however from what i noticed people just spam their videos or links in them. Forum readers become blind to this type of stuff or even report it. Imagine if someone just threw a rock through your window and said "hey buy this now" you wouldnt take them serious and be angry. Reddit is another rough nut to crack. Most new people will try and spam links on reddit to get views which can destroy you. Reddit people have their own laws and will deal with you fast. I have been part of many Facebook gaming and youtube groups. This is another train wreck of people spamming endless links of videos and no one even watches them.
Posting is all about being trusted in the forum or community and if your not none will work for you at all.