[dlss]

I did _not_ know about the excess inventory. Do you mind posting a source?

It just seems like someone would be willing to pay $0.001 CPM at least for those impressions...

(edit: this HN post, interestingly enough, seems to be the top of my google searches for this :p)

[mrkurt]

I'm the source! Although you can identify excess inventory on sites if you know what to look for and pay enough attention. Browse around the NYT site and you'll see ads for the NYT, Google Adwords, and probably Google display stuff. This is excess inventory, usually. Ads for your own company are called "house ads", the others are generally referred to as remnant inventory.

Now, someone will almost always pay $.001/CPM to serve ads, but it's usually not a great deal for a publisher. Ad serving costs are higher than you'd expect, a pageview might end up requiring calls to 10 paid ad tech services for instance (demographics, audience categorization, etc). The NYT is likely losing money when you see remnant advertising, they'd be better off not serving that impression at all.

There are also a number of companies that just won't run remnant stuff, or won't run ads for reasonable sounding CPMs. Conde Nast, for instance, has fixed CPMs that their sales people can't bend from much. They feel that selling for cheaper would dilute their value. Some of the properties even feel like cheap looking remnant ads make the site seem less "premium".

The last sentence here is pretty telling: "since the site had excess ad inventory pre-paywall, the decline won’t affect the ability to satisfy demand for premium units".

http://blogs.forbes.com/jeffbercovici/2011/04/21/ny-times-sa...

[z0r]

That's why advertising exchanges are picking up - put up an auction for each impression for which you have no ad to run, maybe set a reserve, and you're off to the races!