Ask HN: How do you identify what is a small initial market?

[Richallen1]

I have heard a lot about going after a small initial market and try and get a few dedicated users to love your product before expanding out. My question is what are some good tips for identifying a small initial market? What's too big? Should it be geographical?

[brudgers]

In the context of startups, my understanding is that it's not enough to identify a small initial market (e.g. Julius Caesar impersonators), ideally it should have some reasonable potential to be huge in the future.