We are all aware of the KISS principle: Keep It Simple and Stupid. Let me introduce your a similar principle: Keep It Simple and Small.

Maciej Cegłowski who created Pinboard deliberately wants to avoid rapid growth.

“I have seen a lot of free services burn up all their development time scaling for users,” he said. He has no plan to cap the gate fee as more people sign on. “I am tempted to just let it go up and see what happens,” he says. - http://news.cnet.com/8301-19882_3-10310347-250.html

It gives you time to try out different features without upsetting many of your user base.

What if a little site you love doesn’t have a business model? Yell at the developers! Explain that you are tired of good projects folding and are willing to pay cash American dollar to prevent that from happening. It doesn’t take prohibitive per-user revenue to put a project in the black. It just requires a number greater than zero. - Don’t Be A Free User

Why there has to be an exit strategy? If you love what you are doing, and you want to do it for the rest of your life. Why do you need an exit strategy? For some people, it might be better to strike it alone, by keeping it small and having a business model.

Make a living without being beholden to a boss or investors. - Maciej Cegłowski