[Editor's note: this article was written by Charlie Morris in August of 1998. As such, we cannot insure that information enclosed is up to date as of the time you are reading it. Please contact the vendors discussed for updated information on their individual offerings.]

Real Media's, Accipiter's and NetGravity's offerings are the top of the line for commercially available products. They have the features and flexibility needed by large Web sites, groups of Web sites, and even ad networks. They can do all the standard types of targeting that the lesser lites can do, plus some other neat tricks having to do with profiling individual users. They all offer very detailed online reports that incorporate all the targeting that has been selected. These packages can create not only traffic reports, but reports that project available ad inventory, and reports that compare different campaigns. Reports are accessed online, and are customizable and exportable. Of the Big Three, only Accipiter's AdManager offers automated e-mail reporting (a new feature in version 4.0). All three do make their API available, so a bit of custom programming shouldn't be too huge of a project.

None of the Big Three have a set price - they all want to charge a "subscription fee" based on your traffic. They want a piece of the action, and in the end, I'll bet that the price for one of these systems is usually negotiated with each buyer. Accipiter and Real Media also offer complete ad management services.

The differences among the Big Three have mostly to do with the fine points of targeting, and the platforms that are supported. Beware! Some of these packages won't work on some versions of UNIX.