Most non ecommerce websites today are monetized using Adsense. However, revenues using Adsense are often minimal, since CTR rates are low.
If you are selling any other product or service, directories can be used to cross sell or as on addon. Niche directories often help you to build a valuable database of companies in a particular industry.
Since CTR rates are low if PPC programs are used, it is advisable to consider other options like:
1. CPM ads
a. Creditburner – Pays per unique visitor to the website, minimum payout $2.5
b. Voxant
2. Linkbucks – if you are offering free directory listings, you get paid every time a link is clicked.