As I have shared before, you are not really promoting because these places are all site owners promoting to site owners. The code that has yet to get cracked is for a promotion site, that has site owners promote to an audience that does not own a site, knows nothing of coding and could care less about rounded corners etc. Such promo sites that are free simply do not exists. Every promo site boasts of exclusive this and that, reality; there is nothing exclusive and not one has anything different than the other.
Why do you think so many site owners are staff on other sites? It's because their own sites are not active enough to keep them busy. Many do not want to even hear this perspective, arrogance clouds sound judgment. Most want to hear, your site is awesome, super theme, stellar content.... Problem is, you do not need to hear that from other site owners, you need to hear it from a potential member who knows nothing about forums, sites etc.
Look at FP, the same core member base are members on just about every other site found here and then some. All site owners providing content to each other with very few with an external followings.
Ask yourself this, why do you hang out at these sites so much, if they really worked you would be far to busy to hang out, you would come promote and leave, instead FP has far more topics that are not about promotion at all, reason? People go where the action is.
I have found 10 forums on FP that do not even need to promote here, there core members are not what you see here. They come drop a bullet promo info line and leave.
So for those who say then why am I here? I do not own a forum, There is no code here that will be of use to me, I come here because I got sucked into the same black hole many others are in. I'm not here as much because I've found it simply does not work. This said, there is the back link benefit but even then the new algorithms used by Google are looking at the value added by relevancy. Meaning, you may have 500 back links but if only 10 of them relate to the content of your site, then only those count.
This is my perspective, I can almost guarantee 90% of you will not agree. Hence the proverbial due loop is reality.