If you intend to run an extensive online branding campaign over dozens or hundreds of sites, you’ll find it much easier to use a network, which automates placement and reporting. For an intermediate solution, try a self-service solution such as AdReady, which automates the creation and purchase of ads.

You might pay a premium of 10 to 15 percent over the cost of direct placement if you use an agency or a network to place ads. The cost per thousand (CPM) on some ad networks is fairly low, which indicates that their audiences are rather broad. If you plan to run ads on only a few sites, you can probably handle placement yourself.

The following list has many online advertising networks and directories. Confirm that the network you select offers sites within your specific channel of interest or target demographics. Sometimes, a specialty network is a better solution, particularly for B2B advertisers.

Online advertising networks and resources: