It's extremely common for us builders to spend all our time building something cool and then thinking, hrm, I wonder if anyone would pay for this? That's why I

It's extremely common for us builders to spend all our time building something cool and then thinking, hrm, I wonder if anyone would pay for this? That's why I like the advice to do a business analysis first: think out the monetary plan, validate whether people would buy, etc, before writing the code - I totally learned this the hard way. That said, it's never a bad time to start looking at marketing. For metrics, you may want to look at web stats, such as traffic levels and sources, to help with your marketing/funnel, and customer stats: which features are used, which are not used, which are started but not completed, etc. This can guide development focus. One fun metrics idea is, find which feature seems most correlated with whether a user becomes a long-term subscriber. Then tweak your tutorial/tour/FAQ/etc with the goal of getting every user to successfully complete that task.