When you build up you business, beyond differentiating, you want to build up barriers to entry to make it more difficult for the other guys to copy you.

Here are a number of typical barrier to entry:

• Capital intensive industries (airline, mobile operators) / capital requirement. The bigger you are, the better the economics are
• Limited goods e.g. spectrum
• Regulation / licencing e.g. mobile operators again!
• Quasi-monopoly / dominant market share: e.g. Microsoft, Google
• High switching costs for end-users
• Access to distribution channels
• Lobbying power
• Best pool of talents / R&D engineers; ‘A-player’ team
• Speed of execution
• Reputation e.g. banks
• Brand name e.g. Mc Kinsey