I don't follow greg on Twitter... you should be able to find him with a simple search. in fact I try to use it as little as possible anymore. If they don't want me than I don't want to use them. :)

You invest as an anarcho-capitalist by removing yourself as much as possible from the system supported by government looting. In my case that's building a small hobby farm that produces the lion's share of my family's food.

It means having a pool of real savings, a la Austrian Economics, in gold, silver, property that is then leveraged into counter-party risked based investments. It means homeschooling your children (investing in their mental and emotional well-being).... etc.