In order to understand why we have not really solved many of the challenges of digitalisation and especially the financing of media through advertising, one has to look back historically at the invention and development of ad servers. The first ad server was developed in 1995 by Focalink Communications, a company that was later renamed 24/7 Media and eventually acquired by WPP. The first ad server was initially called Mango, and from 1996 Smartbanner, and was the first solution for the management and delivery of online advertising.

Further information:
Back to the Roots (of the problem) - Central vs. Local Adserver