Like I mentioned in the Ebert article, I've been testing out ad networks on subpages of Wopular for the past couple months. I don't want to put any ads on the main channel pages until I've settled into something; also, I want to reserve those pages for premium sponsorships.

Premium vs. Remnant Inventory
First, there are two types of ads - ones you sell yourseft (premium inventory) and whatever's left over (remnant inventory). Since I don't have a sales team working for me, and I'm not ready to sell ads myself, let's forget about premium inventory for now. All I have right now is pretty much remnant inventory, and the easiest way to fill them is with ad networks. They tend to have really low rates, but they do all the work for you. All you have to do to start making money is stick their javascript code into all of your pages. Voila, you have ads on your site, and you're making money. Did I mention the rates are crappy?

"This site has ads. It must be rolling in the dough!"
I often get this comment from friends - "This site must be doing well, it has ads." Not necessarily. Most of the time, the answer is no, they're not doing that well. Anyone can put ads on their site. Even if it has no traffic. There are ad networks that'll accept anyone. If you're looking at a website that you've never heard of, chances are they're not making any money. Alright, maybe I should say not a significant amount of money because most of them are probably making a couple cents a day. At the end of the month, they make enough to buy a dvd. For some, that's good enough, but I wouldn't say they're rolling in the dough.

Testing out the Ad Networks
I've been testing out several ad networks - Chitika, AdsDaq, Advertising.com, and AdBrite. Specifically, I've been testing the 300x250 ad unit. So far, the effective CPM (cost per thousand pageviews) ranges from $0.1 to $1. That is, for every thousand pageviews this site gets, I get anywhere from $0.1 to $1. You do the math. Even with millions of pageviews, you can't make enough to pay the bills. That's why you can't rely on ad networks; you only give them what you can't sell. But you have to start with them because they're easy to set up, and you don't have a sales team yet.

Testing them out is a time consuming process because I want to give each network enough time to adjust for random spikes. Because an ad network won't fill your entire inventory, you have to sign up with a bunch to get a nice fill rate. I'm settling into a decent ad network chain though. Also, I think it's against policy to tell how much I'm making from each, so I'll just tell you how well they perform relative to each other.

• Chitika
  Chitika has an interesting approach. They only sell ads on pages visited by users coming from search engines. People coming to the site directly will not see these ads. Because websites, on average, receive 50-60% of their users from search engines, there's enough inventory to make a decent revenue. Because the ads are based on search keywords, they tend to be highly relevant and targeted so click-thru rates are higher than other ad networks. For Wopular, they are the best performer. I don't include them in my ad network chain because only users coming from search engines will see their ads.
• AdsDaq
  Here's another interesting approach. AdsDaq allows you to set the minimum CPM for ads to be shown on your site. If an ad doesn't meet your minimum, it's sent to another network of your choice. They're on par with Chitika. The quality of their ads are decent. You do get a decent amount of teeth whitening and get fit ads, but no flashing ads, no ads with sounds, and no video ads. I put them at the top of my network chain. I would set a minimum of $1 CPM. Anything below that goes to Advertising.com.
• Advertising.com
  It's not bad for a traditional ad network, in terms of CPM. Advertising.com ads are high quality and professional, probably the best of the bunch. Seeing one of their ads on the site just makes it look a lot more professional. Customer service has been great too. I had a problem with their code, but we were able pinpoint the problem and fix it - it was my fault.

• AdBrite
  By far, AdBrite is the worst performer of the bunch. They have a lot of junk - flashing, seizure-inducing ads, videos with audio turned on by default, and lots of get-ripped ads. It's obvious why they're the worst performers because they serve a lot of garbage that will not only annoy your users, but also make your site look like garbage. Sure, you can filter out the offending ads, but it's a time-consuming process. I also didn't notice much of a difference in performance when I picked different categories (entertainment, sports, politics, etc.). They do have full-page ads that garner $1-$6 CPM; more often than not, it's closer to $1. But the good thing is they're one of those networks that accepts just about anyone. I would sign up with them first just to get the ball rolling, and slowly weed them out as you move up the ad network ladder.
• What About Adsense?
  Last year, they had not only banned Studio Briefing, an entertainment news site, from using their ad network, but they've also excluded the site from Google's search results - for no apparent reason. If you've been banned from their search, your site's pretty much toast. You see, websites get a majority of their traffic from search referrals, and Google is the source for a majority of those referrals. Studio Briefing was unknowingly engaged in behavior that Google deemed ban-able, and their explanations for banning was cryptic. The site has since been re-instated, but only after Lew Irwin's high-profile press contacts denounced Google publicly for it. I'm sure AdSense is a great program, but I don't want to take a chance of getting delisted.

I signed up for a bunch, but these are the ones that accepted me. Chitika and AdsDaq are highly recommended. Advertising.com is excellent for a traditional network. AdBrite, although crappy, is probably the easiest and quickest to setup. I was also accepted by Casale, but I haven't had time to try them out yet. I was rejected by Tribal Fusion and a couple other high-paying networks. I think I'll stick with this setup for a little bit.