Is it hard to build, market and maintain a web app that makes at least $1000 a month?

I chimed in at Quora to a question about whether it’s hard to build a web app to make $1,000/mo. My answer was simple. It’s not hard, but unless you’re aiming significantly higher than $1,000/mo, running a web app that should be available 24x7 simply isn’t worth the time, stress, and added responsibility.