When you park domains, make sure you experiment with several parking companies.
Each one of them provide a different default template and various options. Also a domain which does not perform with a parking provider may well exceed your expectations with another one. Some Parking companies are better at monetizing traffic on hi-tech products while others may be best at bringing revenues from people looking to buy clothes or rent a flat.
A big difference we also see is how different Parking Services monetize different GEO based traffic. Some are very strong on US based traffic, while others are stronger on EU traffic. Others have looked at covering Asian traffic…
As with most things in business: test, test and test again… Or better still use the Above.com Parking Manager to do this all for you automatically!