What are the ways to gain a monopoly? [closed]

Question

Gaining a monopoly is of course something that is interesting for all entrepreneurs, is it still possible to make one? If so, how?

I turned this question into a wiki, feel free to add possible answers.
@Alain Raynaud I cannot see that this worked out as a good idea. Now it turned out as a badly rated question, with no answers (apart from my initial points)
Generally speaking, if a question is trying to build a list of possible answers, then it's more appropriate to be a wiki, since there is not one best answer. That being said, the question itself may not attract many answers.

Kirk Strobeck · Answer 1 · 2011-08-09 19:00:11Z

A monopoly can be achieved the following ways:

Getting perfect patent coverage
Owning land will sometimes create a local monopoly. For example a skicenter
Being dominant in an area of business where network effect is strong and there are barriers to changing. (I thought about Facebook until Google+ came along. I do not have other good examples).
Having an exclusive sales deal with a monopolistic producer
Being the only provider who has been approved by an approval agency or government

Of course, as with all monopolies, if one exploits the position too much, competition will come.

closed as not constructive by TimJ♦, Christian, jimg, Karlson, Chris Fulmer Nov 30 '12 at 18:20