Among the things the two organizations agreed upon are sequential liability for media bills, and guidelines regarding the posting of privacy policies and the cancellation of campaigns.
Though it's unclear what the final impact will be on the troubled Internet advertising industry, both groups felt that the agreement represented significant progress toward making online media more manageable.
"I think we have come to a great meeting of the lives with the IAB on this thing," said Mike Donahue, 4As executive vice president, member services.
The organizations expect to move on to new issues, including measurement and guidelines for third-party ad serving. To that end, the IAB is launching an audit covering all aspects of online measurement with PricewaterhouseCoopers.