In digital advertising context, ad sequencing is the fact of scheduling a particular and ordered ad sequence made of different creatives.
Each individual exposed to the campaign will see the complete planned sequence, provided enough exposures.
The serie of distinct messages can be used to claim different arguments or for story telling. Within an ad sequence, creatives are often under the same creative concept.
In complex ad sequencing, advertisers can control the progression and delivery of multiple ad units, using any trackable event.
For retargeting campaign, ad sequencing may be used for giving progressive benefits.
Creative sequencing is a common feature of ad servers and is usually cookie-based.
An example of ad sequence :
Image credit "The Science of Social Media Advertising"