Do You Make Money From Your Forum?

I am running three forums and all of my forums are monetized with Google Adsense. The average earning on my forums is around $8 per month. Well, this is a negligible earning but since I do not use premium software and paid addons, I do not have to spend a lot of money on maintenance, I can maintain my forums from the revenue generated by the forums.
I make very small revenue on my forums which is not enough even to maintain the site. If you open a forum with an aim to make money, never do that. It is really difficult. You might be able to make money form blog but making money from forum is harder as it is really difficult to get organic traffic on forums.
I have implemented adsense and amazon ads on my forum but I am yet to generate revenue from my forums. At this moment making money from my forum is out of question as traffic is small, and activities are also very few.
At this time I am making a small amount of money on a forum I co-own with my other half and not making anything on another forum I own at the moment but that forum is quite new so understandable.

I would like to be making enough through my forum that it pays for itself but for now, will keep working on them/