> Question is: what can I do to get the service out of its current letargy and maybe make it a viable side-business (not planning on making a living out of it, really)?
How about establishing a small but steady stream of improvements to keep the interest, and charge for the password protected maps in a freemium model? Be sure to do lots of testing e.g. A/B testing, to assess the impact of your changes.
Nonetheless, what I see here is that you have an audience, but no visible business model and possibly an inadequate revenue model. Having this will help you develop a unified plan and maybe even give you a few ideas on what changes to make on your website.
You might want to experiment with some of the ideas you receive on YC as well.
How about establishing a small but steady stream of improvements to keep the interest, and charge for the password protected maps in a freemium model? Be sure to do lots of testing e.g. A/B testing, to assess the impact of your changes.
(Disclaimer: I have no experience.)