[endriju]

In 2014 I have worked on http://exmerg.com but it wasn't until recently for it to start generating some passive income. Still, the infrastructure costs (AWS) are higher than the revenue, so money wise the balance is passive (not counting the hours spent building the service which I could use for client work).

The positive side effect of building it was having additional source of motivation to learn new things in various fields like UI/UX design, cloud services, business operations and other SaaS related stuff.

The main lesson it taught me was how much hidden work needs to be done to attract users and monetize a web service. I think a start-up that would make it easier to deploy, maintain and monetize web services would be an interesting one.