Shared Libraries are files that are repeatedly used by ads, and therefore are stored in a centralized location and cached by end users' browsers. This improves performance since there is no need to download them each time an ad is displayed. For example, in the Sizmek Ad Suite (SAS) ad serving client,
ebHtml5Banner.js, is a shared library. Every SAS Standard or Rich Media ad uses this shared library, it rarely changes, and it is served from a centralized, fixed location so that it can be cached.
The IAB endorses using shared libraries to reduce the ad load. The following is an excerpt from the IAB guidelines:
Browser caching capabilities benefit all parties by eliminating the need to download previously requested resources that already exist on the user’s device. Advertisers (Creative developers) are encouraged to take advantage of browser caching functionality by linking to shared libraries hosted on the Ad Serving party’s (Publisher ad server or third-party ad server) domain that are used across campaigns.
Depending on whether the SAS tag is placed on a secure or non-secure page, shared libraries are located in the following paths:
Note: The code in the shared libraries is updated regularly; therefore, file sizes that are noted in the following sections are estimates.
3rd party shared libraries are located in the libraries folder, https://secure-ds.serving-sys.com/BurstingcachedScripts/libraries/. File sizes in the following sections are for the secure path.
Note: The non-secure file path for the libraries folder is: http://ds.serving-sys.com/BurstingcachedScripts/libraries/.