In the world of Digital Campaigns whenever creative is being served through Ad Tags it means the ad delivery is being tracked using two sets of numbers: The Publisher's numbers (as reported by their Ad Server) and the Third Party Vendor's numbers (as reported thru the Ad Server of the Vendor used to traffic the ads). The difference between these two sets of numbers is referred to as a Discrepancy.

What causes discrepancies?
Discrepancies are a by-product of counting methodology. In other words it's the difference between when a Publisher considers an Impression "counted" and when the Third Party considers the same impression "counted". Additionally, different vendors may count their impressions at different times in the ad delivery process so discrepancies can vary by vendor. Here's another way of looking at this:

If either ad response fails prior to the 3rd Party’s count (Vendor X does not respond with content, Vendor Y’s content does not load), then the impression is not captured on the vendor's end. The result is a discrepancy between the Publisher and Third Party impression counts.

What is considered a normal discrepancy?
Agencies and Publishers typically consider a discrepancy of up to 10% normal, and most vendors will not troubleshoot anything less than this amount. My experience has been that most discrepancies range 2% - 5% depending on the vendor.

How do Publishers compensate for discrepancies?
When trafficking a campaign that is billed using 3rd Party numbers, a Publisher will "overbook" the goals on the campaign by a default or anticipated discrepancy percentage to ensure that the Advertiser's contracted goal is met.

For more on discrepancies you can read about the Impression Exchange Solution: An industry-wide standard mechanism designed to create immediate awareness and transparency around discrepancies.

A (creative) Ad Tag is a piece of HTML or JavaScript code that is inserted into the source code of a web page via an Ad Server. Simply put, the Ad Tag is a digital placeholder within which content will ultimately display.

As illustrated below, when an Advertiser traffics an Ad Tag to a Publisher, the tag is uploaded to the Publisher's Ad Server. When a page that includes the code for the uploaded tag is loaded on the Publisher's site, a 'call' is made to the Advertiser's Ad Server, which then returns a call that places the relevant content into the ad tag.

What are the benefits of using Ad Tags to serve creative content? Many.

But if I had to give my #1 benefit it would be this: Serving content within an Ad Tag allows the Advertiser to rotate as many content pieces as they like, whenever they like. Since all of the action is happening within their Ad Server this allows for quick and easy performance optimizations.

And the #1 concern associated with running Ad Tags? The Advertiser can rotate whatever they like, whenever they like. Since updating content within tags (a.k.a. making changes on the back end) does not require trafficking anything new, Publishers can be caught unawares in the hands of unscrupulous advertisers, so random spot checks are never a bad idea.

For anyone on the receiving end of digital creative (Traffic Dept, AdOps), a basic question we seek to have answered is "What type of creative is the advertiser running?".  Creative Type is a concept that often trips up front-end folks as the question is routinely misunderstood as "what vendor is the creative coming from?" or "what product-assets or sizes are they sending?".

Typically Digital Creative falls into one of three types:

1. Static Creative - An image or a graphic that does not move – Typically a GIF or JPEG.
2. Flash Creative – An image or graphic that is (self) animated. Also referred to as STANDARD ADS.
3. Rich Media Creative – Image or graphic with which users can interact (as opposed to solely animated) thru mouse over or click. These ad units may appear In Banner - within the confined ad space such as video - or Out-of-Banner such as expandable ads, floating ads, page take-overs, and push-downs.

Why does the person receiving your creative need to know the type being trafficked? Two main reasons:

1. Different types of creative require different turn around times. Knowing what's coming helps to better level-set.
2. Some sites, or pages within a site, have creative type restrictions that may require separate items to be trafficked. The sooner limitations are brought to life, the quicker they can be addressed and remedied.

Now you know the importance of knowing Creative Type.