My forum is 1.5 years old with 750,000 pageviews a month and 300,000+ posts.
I made $5 to $8 a day with a single Adsense banner on top. That’s $150 to $240 a month; That’s abysmal.
I learned pretty quickly that forums aren’t money makers, but money making TOOLS. You have an ever-growing base of people interested in the forum’s niche. It’s up to you to leverage that into profits that exceed the peanuts the pathetic Adsense banner trickles in (at least it covers hosting).
The first thing I did was to remove the adsense banner completely. Yeah, you can be sneaky or blatantly annoying with your ads and either integrate them into the forum navigation/mechanics or have big 240x240 after the first post of each thread, but that really depends on the nature of your forum. For example, my community is very “in-for-the-long-run” as opposed to more compulsive come-and-go communities. I have a very high post/user ratio that exceeds most other forums.
The next thing I did was randomly throw up an affiliate link banner every once in a while rather than keep one there. That way, my users had less “banner blindness” and would pay attention to a banner that suddenly appeared there when it wasn’t there all week. I started out with a simply ringtones offer and would cycle it on and off with other products in my niche. I went from $5 - 8 a day to $15+ a day. Often I’d hit a good product at a good time and push even higher.
Then I added an opt-in box for my users to receive a direct newsletter about forum summaries (that community volunteers made for me) as well as general information in the niche. Before the opt-in box, I emailed a sample of 100 random users but I got a lot of “how did you get my email” responses and decided it wasn’t “right” to spontaneously email forum registrants just because you have their email.
Now that they’re opted in, I can create joint ventures with others in my niche and recommend them the products/services of others because I’m well-trusted.
I now make about three figures a month off of this 1.5 year old forum. It’s nothing to write home about, but it’s still young and I’m still refining my monetization techniques. Would I make a forum purely for profits? No way. You need an interest to really engage yourself with a forum. I still have fun posting in my forum and updating it.
My forum is a growing community of people THAT TRUST ME. This alone is worth more than the three figures a month I make off of it. To maintain this trust is also the reason I don’t have annoying advertisements (I would never implement Kontera in one of my forums).
Of course, not all forums necessarily need such trust to make a lot of money. If you’re getting a lot of impulsive search engine traffic that are just here for a quick tidbit of information (e.g. “how to remove Taz.Black.W32 virus”) with users that aren’t in it for the long haul, you’re more likely to implement “nuisance monetization”.
I put a decent amount of work in to receive those three figures a month. More realistically you’ll receive a single digit income per day with even solid forum activity and a simple adsense banner. You can fiddle with affiliate commissions to increase that number slightly, but don’t expect high yields from a forum.