Personal finance isn't just about building up net worth—it's also about making money available when you need it.  Just like a business, you have to worry about your balance sheet and your cashflow statement.  Having a lot of money locked up in investments isn't helpful when you need cash to cover expenses today.

This is the logic behind the emergency fund—hold a couple months' expenses in fairly liquid form, like a savings account or US Treasury I Bonds, to smooth over unexpected changes in expenses and income.  Establishing an emergency fund should be your first act before considering any other kind of investing.

How much money should you keep in an accessible place?  To make that decision, you have to balance two opposing forces: the risk and cost of having too little, and the cost of not investing in something with a better return.

In an earlier article on nontraditional investments, I mentioned Lending Club.
Lending Club is the leader of the pack of a new breed of peer-to-peer lending platforms.  You can join Lending Club as a borrower or as a lender; for investment purposes, we're interested in the latter.