Google AdSense alternative for the Netherlands
A good method to find the answer is: Use the same network as other top websites in the Netherlands (or many other countries) are using, excluding AdSense of course:
- Browse the top 100 Dutch websites and take note on those who uses text and banner ads
- Find the companies behind their ad sales
- Contact those ad placement companies and ask how to join their network
A free place to find out which are the top sites in any country is Google Ad Planner
If your client has a website with loyal visitors and a common interest, your client can try to sell ad placement directly to anyone that wants to promote something to those visitors.