REI and market population

[Gabriel T.]

I noticed most of the discussions on here involve the biggest cities and metro areas in the country; DFW (7.2m metro population), Houston, Chicago, Atlanta, Seattle, Denver, San Francisco, San Diego, Columbus, Indianapolis, Detroit, Memphis all have populations over 1m. When any market is discussed it is usually about appreciation vs. cash flow. It goes without saying the bigger your market the more opportunity, but what are pros/cons of investing in smaller areas?

As someone just starting to learn about real estate I wonder about how market population affects people's strategies. What are the differences in big/small markets and how do small market investors make up for a smaller population?