Introduction

Ad networks have come a long way since the early days of online advertising. By now their advantages are well-established: they are cost effective, efficient and provide broad reach. The networks have become far more transparent to both their publishers and advertisers. They've become more vigilant towards screening out objectionable content and copyright violations. They've improved their targeting technologies for advertisers and yield management for publishers.

However, some of their pitfalls are also well known. Advertisers have less control over where and when their creative is delivered. Some ad networks still offer mostly remnant inventory. Their traffic and delivery can be unpredictable, to say the least. And they face competition from other sources: affiliate networks, Google and Yahoo!'s content-targeted paid search programs and even their own publishers.

Both advertisers and publishers must be vigilant about avoiding certain hazards with ad networks. If you consistently encounter the following problems, it might be time to find a new network. 

Author notes: Marissa Gluck is founder and managing partner at Radar Research. Read full bio.