Thanks for posting this. Very informative read<p>I think my most successful side-project stagnated at about $100/month in monthly revenue (which was roughly break-even given my operating costs). When I couldn't get it to grow beyond that, I eventually killed it. I actually didn't have much churn, but getting new signups was difficult (and expensive) and I just wasn't charging enough to make the whole thing worth my trouble.<p>Things I learned:<p>- Spending money on Adwords was basically the same as setting my money on fire.<p>- Paying bloggers to review your product seems sleazy, but the popular bloggers in your niche expect it (and the more popular they are, the more money they demand) and it actually works better than CPC advertising.<p>- If you think you've found an under-served market, chances are other devs have noticed it too, and they probably have access to more money and resources than you do as a solo founder (it's always great to see a competitor with better stuff launch 2 months after you, so you cut your price, then they cut theirs, so you cut yours more, thinking: "I'm a lone dev, this is a side-project, I don't need the revenue, I can surely win a price war." Which ultimately ends with subscriptions priced too low to be worth the hassle. But at least it was a boost to the ego that those other guys saw me as a competitor).<p>- If you whip up something really quick-and-dirty in Ruby-on-Rails, there's a good chance you've failed badly at architecture and adding new features to keep up with the competition will be difficult :)<p>- Just use a third-party mail service like mailgun, mandrill, et. al., All my transactional email was going to people's spam folders until I spent many hours learning about DKIM, etc.<p>- Stay away from the education market :D