gunnar,
o/t: Based on your comments I think you should go take a good look at China Yida (CNYD). They own tourist destinations, a t.v. station, exclusive rights to post ads on trains, and also 30 billboards. They are leveraging their advertising network to draw tourists to their destinations and have 50%+ net margins to show for it. Use geoinvesting.com for research.
Owning an advertising platform is a great advantage if you branch out. Ted Turner did this when he owned a large, highly profitable billboard company and then bought a small, unprofitable TV station. He just filled all of his excess capacity billboard space with ads for his own TV station, and Turner Broadcasting was born. The business model wouldn't have worked without the leverage of free - and effective - advertising
-Adam
"What goes down must come up" Inverse Newton