IAB standard ad units are a range of ad formats promoted by the IAB to facilitate online and mobile advertising.
The adoption of ad standards is particularly important because a display campaign can be delivered on several hundreds or thousands of publisher’s websites by the means of an ad network.
Current and potential standard ad formats are reviewed on bi-annual basis by the IAB’s Ad Sizes Working Group. The last update and big change was in february 2012.
IAB ad units are mainly defined by:
initial dimensions in pixels
maximum expanded dimensions
max initial file load size
max additional initial file load size
maximum animation length
Some ad unit definitions: