What is ROS (Run of Site) or RON (Run of Network)?

Definition

Run of site (ROS) is a phrase used to define inventory (page loads) that publishers are unable to forecast ahead of time. As a result of this they don’t have advertiser spending lined up. This causes them to dump such inventory at dirt cheap prices. Another form of ROS inventory is inventory coming from some sections of publisher site which cannot be sold as premium inventory. For a newspaper site, such sections could include, job postings, obituaries, personals etc. Such sections have very low value for an advertiser and are thus given up as ROS inventory.

A lot of ad networks buy ROS inventory from publishers and try to make a profit by either reselling it or running direct response or branding campaigns on them. Such a collection of ROS inventory on an ad network is called Run of network (RON).

Typically ROS/RON inventory is prices quite cheap compared to premium inventory. As a result it is expected that it will perform poorly compared to premium inventory.

Why this happens?

Pages that do not have good content cannot be sold as premium inventory. There is nothing much one can do about such pages. They will end up as ROS inventory. A bigger problem for the publisher or an ad network is when they have a surplus of impressions for a given month and no advertisers lined up to serve ads. Such a case can happen either when a publisher does not make accurate forecasting about their future traffic or there is a spike in the traffic coming to the publisher. As a result the sales team sells only what was forecasted. If the publisher receives more traffic than forecasted then it will end up wasting those extra impressions. Since media buys are done weeks if not months ahead of time, any changes in inventory cannot be sold immediately.

A balance is met when another ad network or advertiser steps in and offers to buy such inventory. The catch is that the advertiser will not pay premium price for such inventory. They will just buy it at ROS price. This lets publishers dump their surplus inventory at whatever price they can get and advertisers get a steal deal. The only catch for advertisers is that they can potentially end up with a mixture of ROS surplus inventory and real ROS inventory.

There is a big difference in the prices of premium and ROS inventory. For example, the CPM price of premium inventory might be $10.00 while ROS might be as low as $1.00. This is the reason why forecasting is one crucial aspect of publishers’ ad operations.