Passback: How to Sell Direct and Keep Your Network

A passback is what happens to an ad slot when nobody has bought it: instead of showing nothing, the slot is passed to another source, usually the ad network you already run.

It matters because it settles the question that stops most publishers from ever trying direct sales. That question is "what if I end up earning less than I do now", and a passback, with a floor price above what your network pays, is the answer.

What actually happens in the slot

Each slot is offered in order of what it pays. Your direct advertisers are asked first, because they pay the most. If none of them wants this particular impression, the slot falls through to whatever you had before.

The reader sees one ad and has no idea any of this happened.

Why this makes the decision easy

Without a passback, selling direct is a bet. You take inventory away from a network that was paying for it, and if you do not sell that inventory you have lost the difference.

With a passback, the arithmetic is on your side:

	Network only	Direct with passback
Impressions in the month	40,000	40,000
Sold directly	none	24,000 at $12 per thousand
Direct income	$0	$288
Remainder to the network	40,000	16,000
Network income at $0.90	$36	$14.40
Total	$36	$302.40

The network earns less because it has fewer impressions. That is the point, and the trade is $21.60 of network income for $288 of direct income.

The technical part, briefly

There is one implementation detail that decides whether this works at all, and it is worth knowing because it is where cheaper setups fall down.

The passback code has to run inside your page, not inside a frame. Most ad network code, AdSense included, checks what page it is on before deciding what to fill with. Run it inside a frame and it sees the frame rather than your article, and it either fills badly or does not fill at all.

If you are evaluating platforms, that is a specific question worth asking: does the fallback execute in the page or in an iframe.

What else a passback can be

The network is the obvious answer and it is not the only one. An unsold slot can hold anything, and the good options are all worth more than an empty box:

• Your existing network code. The usual choice: what you do not sell keeps earning from the network. By default one unsold view in ten shows your Advertise Here card instead, and you can switch that off.
• An Advertise Here card linking to your own rate card. Unsold space advertising your advertising, to people already reading your site. See why that page earns its slot.
• Your own promotion. Newsletter signup, a product, a page you want read.
• Nothing. Only when an empty box would break your layout.

Most publishers starting out should use Advertise Here on their most visible slot and the network everywhere else. The most visible slot is where a potential advertiser is most likely to be looking.

Fill rate stops being a worry

Publishers new to direct sales fixate on fill rate: what share of inventory sold. With a passback it is not a problem to solve, it is just a number that tells you how much of your inventory has direct demand.

Sixty per cent fill is not forty per cent wasted. It is forty per cent still earning network rates.