For one of my first full time jobs working for a b2b magazine publishing company I was assigned to implement rotating banner ads to an existing homebrew CMS. It included several customizations and user options. Analytics was included in the tool.

• A custom CMS was used by the company which was written in ASP.Net and C#.  About a hundred websites used this CMS and the advertisement system was to be included as an additional option.
• Created custom rotating advertisement system for entire CMS. Customer included a specific sized banner ad and it was displayed based on either cost-per-view or cost-per-click strategies.
• An application for managing the advertisement spaces/leads/sales was also implemented to handle this ad system.