I keep seeing sites like http://shoppingmall.com/ are these sites designed for pay per click purpose or something else?
This are parked domains. They cant be called sites. Domain owners parks there domains with parking services like SEDO and they get paid for each and every click you make in that site.
yes you are allowed to do parked domain and get the revenue from the registrar. It's good income whe you dont have the contents for your site yet.