When booking banners different parameters are needed compared to print ads. Not only can the way of invoicing be different (e.g. CPM based, or upfront, or ...) but also one and the same banner position can be sold several times, since different banners can rotate on this position.
The Banner book&publish module facilitates these requirements; book banners for 1 or more websites, check the availability of the positions, optionally indicate how many times a banner can be shown to the same website visitor, connect the banner to the booking (or use a url where it's located) and you're ready!
Uploaded banners are exported to the website(s) with start&stop dates, where a simple rotation script can take care for publishing these online at the right position, during the booked period.