Adweek reports that Revenue Science is forming a new ad network targeting ads based on user behavior across several sites, thus addressing a limitation of behavioral targeting: insufficiently large segments as a result of collecting user behavior on a single site. The announcement comes a month after competitor Tacoda Systems announced plans to launch a similar network.

The firm didn't say which of the companies currently using its technology - which include The Wall Street Journal and Reuters - would join in the collective effort.

The network is designed to allow for flexible participation by publishers, which can buy or sell avails and contribute or purchase audience information for improving the value of avails.

One site could, for instance, learn important information about a group of users and then buy more impressions hitting those users on other sites. Or the site could simply pass on that information to another site. Publishers will set their own prices for inventory and information.