Defensibilities

In the olden days their were lots of 'defensibilities' that a company could have (barriers to entry or ways to get a sustainable competitive advantage). You could have a port or iron mine in the right place. Software business are left with just 4 types of defensibility:

• Brand - awareness or recognition of your brand
• Scale - e.g. Amazon, they are so big they have lower prices, so it's hard to compete.
• Embedding - you embed your software in another organisation so that it's hard to take out.
• Network Effects - you have so many users it's hard to anyone else to 

James Currier of NFX Guild on A16Z podcast:

https://soundcloud.com/a16z/network-effects-taxonomy#t=4:08