The ad network space is cluttered with many players, which makes it difficult to tell one from another if you don’t ask the right questions.

Be sure you have a clear picture of the type of audience you want to reach and the goals you are trying to achieve. Not every network will fit the needs of every advertiser, and using the points described here will help guide you when talking to a potential network partner.

Some basic rules to live by in the ad network space are:

• If you are looking to advertise on a specific site, you will likely end up working with a rep firm because the site cannot support a sales force or needs help monetizing all their traffic. Also consider hybrid ad networks that allow you to choose single sites to advertise on.
• Pure or hybrid ad networks are generally used to extend reach and drive volume.
• Brand advertisers are most often better served by rep firms (to buy those single sites not sold elsewhere) or hybrid ad networks that will tell them what sites they will run on and provide efficiencies in reach.
• Direct response advertisers have many options in the ad network space, but with the pure ad networks they have the benefit of CPA deals to drive efficient sales, as well as the option to dial up or down the volume based on ROI thresholds.
• If you want beyond-the-banner solutions, you can still consider the ad networks, but also look to the rep firms and hybrid networks that offer single-site representation.

Doing your due diligence, while time consuming, is very important. Talk to your fellow media planners and buyers and listen to their experiences. Check out the blogs and message boards on various media planning and buying websites. You may not always find the success stories, but most people are typically willing to let you know when they have had a bad experience.

And that's a really good place to start. Ruling out the bad apples will usually help you uncover the good ones.