Banners can be of any size. New exchange members can be automatically awarded a specified number of free 'credits'. The code which they must include on their pages, along with instructions, will be shown to new members. This default ratio can be changed for all new users, or each user can have their own ratio defined. Extra credits can also be added for any existing member.
Members can modify their details and monitor the success of their banner advertising.
BannerPlus now also includes a referral system so that members can earn extra credits for referring new members to the exchange. Check where your traffic is coming from. Oh, and it's free. It can be freely downloaded and used. It may be modified as long as the copyright information remains intact.