Ad networks and ad servers often provide a choice of tag types to their publishers/users: iframe or javascript. in the case of ad networks or exchanges, sometimes the choice of tags that the publisher uses is up to them and often it is not… however sometimes they nest these ad tags inside of ad servers that in turn use iframes. So an often convoluted series of “frames within frames” persist.

There are various pros and cons of Iframes (see here for a good overview some of which I summarize here), some pros include: Iframes don’t delay the serving of the page, typically loading in parallel with the other page content, there is no chance of name clashes with Javascript variable names if they are inside an iframe.

Some pretty big cons of iframes would include losing the referrer information of the page, which in turn means you can’t do contextual analysis of the page and more importantly you don’t really know where your ad has been running. Ads can’t communicate between each other if they are on the same page, so the coordination for wrap arounds or other things can be lost. You can’t run expandable ads (though some rich media creative companies like OggiFinoggi have come up with ways to “fake” expansion ads with iframes that is kind of interesting), which some users would say is a great benefit of these, but it complicates further the adserving ecosystem adding more heterogeneity to inventory which is now a mix of iframes and javascript tags and it is then unclear what can serve where.

As a demand-side platform helping advertisers buy optimized media, CPM Advisors (CPMa) runs billions of ad impressions per month across various advertising exchanges and we look at a LOT of impression logs. A lot of lower-cost inventory on some of these sources we have seen is hidden behind iframes, meaning most often the referring URL is that of the ad network serving the ads. As a whole, inventory that is served in iframes has a substantially lower price and underlying value than inventory that appears in javascript tags. The extent of the problem on any particular platform including Right Media is unclear, though I would guess that, excluding Yahoo! on the exchange, iframes might be 70 percent by volume if a fair bit less by number of publishers. There are obvious reasons for this, including that companies who would do nefarious things and generate large volumes of traffic often would hide their referring URLs behind iframes (and often, many nested layers of iframes running in parallel), but I do not believe the fairly young ad market yet correctly takes into account this trade-off.

Now there are exceptions. Some publishers like Amazon.com that work with ad networks grudgingly, purposefully put their ads in two layers of iframes to hide their origin AND to stop unscrupulous partners from “stealing” shopper-related data from their pages presumably – but as my other writings would attest I believe that the “sell the same stuff for different prices” world of online publishing will come to an end in the next several years and then this kind of good-quality-site-hiding-behind-frames behavior should be reduced – with the caveat that data use practices in a non-iframe world will also have to be more closely looked at, which I think will happen regardless. Are impressions a commodity? No, not yet but that wouldn’t be a bad thing if we had a real market to buy and sell impressions or “audience”. Let me put it this way – platinum and lead are both commodities but one sells for $1400 an ounce and the other for $1 a pound.

In tomorrow’s market-driven ad world, transparency will be more the norm and anonymous inventory will have its place, but on average will be discounted in price. Thus we may see what one might call the “iframe tax” – less measurability and accountability means more trust is needed which means more risk which means less money for networks and publishers that use them.