What are some alternatives?
When comparing Inout Adserver and Google Ad Manager, you can also consider the following products
VertaMedia - VertaMedia is a Supply-Side Platform designed to meet the demand for efficient ad serving technology and high yield optimization.
OpenX - Ad technology platform available as a hosted service or as an open source download.
Atlas by Facebook - Atlas by Facebook is an ad serving platform that also offers tools for marketers to serve, manage, track, and measure their campaigns.
AerServ - AerServ offers monetization solution for mobile publishers.
PageFair - An ad serving technology for premium publisher and media groups.
ONE by AOL - Ad Serving and Supply Side Platform (SSP)