Inventory for which a given ad trafficker can't be certain where they are in the ad call daisy chain. They may be first or the ad call may have already passed through another platform as part of a daisy chain.

Generally refers to an ad network.

Advertising that matches the form and function of the platform on which it appears for example the ad search term responses at the head of Google search results or promoted Tweets in a Twitter stream.

Network Advertising Initiative. An online advertising industry association focused on consumer education about online behavioral advertising (OBA). Read more at the NAI website.