I have a few users for my app, and 1000's of ideas on how to improve it.
I've been tracking my work in trello, on a public board (my app is still closed source, but i'm as open as possible about the processes of my work).
The development board (in French)
I'm the only one doing development work here, but I've invited my clients to join the board. I instructed them to just "join" any card that seems like it would be useful to them. I only invited paying customers.
It's a great way to focus on what's really needed. But i tend to work on some technical stuffs that don't really matter to them right now (like the last post about aggregation suggests) so I can't always prioritise what's asked.
And I get some Trello gold after every signup, but I'm not sure why I should care.
Ideally, I'd like something similar but integrated in my app, to let users voice their opinions and needs without friction, but I thought i'd postpone that to the time where all the cards with a person on it are already done.
And services like this already exist I guess, so it's not really worth investing much effort in creating a custom solution.