Owning your own banner exchange is an excellent revenue generating traffic tool that you can use to promote your own website network. Plus you make 100% of advertising and traffic services.

The free/paid banner exchange provides a 2:1 banner ration (of which the administrator can change), which means for every two banner impression that loads on a user loads on their website, they get one impression of their banner on a member site. Every other banner impression is filled by a house promoting the exchange. For paid services, this site boasts paid credits and banner advertising on the main website.
In addition this banner exchange has an anti-cheat referral system that promotes the exchange itself. You set the referral credits for your members.
With no extra fees other than hosting, this site is a serious traffic generation and advertising based money making tool.