I started working on Commotion a few months ago, and back when it was just a few early users, it was easy to use email to keep in touch with everyone for things like if they found a bug or wanted to request a feature or was confused by something.
As we've grown, 1-1 email relationships have been tougher to manage and so I'm curious what others do/use at this stage. I've started a mailing list to email product updates and created a public forum to collect feedback to start with. It's a problem I'm interested in tackling and curious to hear others' thoughts.
I think the best way on creating a framework (and building the processes and acquiring tools around it) on this is to start with an audit: what are the "types of communication" you (as a company) do with your users.
Then understand where your users would prefer to talk about these. That is possibly the only surefire way to create a system for communicating with your users.
Product email list is good, encouraging communications in other channels for scale (blog, social, forums, FAQs) also works. I keep a list of stock replies for certain situations where I can't automate informative responses, too.
Even better if you can tie it into the product (we recently added notifications in our SportsTrace app). It's hard because you want to maintain that personal touch but there is only so much of your time to go around!
For features, you can have an online submission system where other users vote those features up like uservoice. And you can have public bug submissions where users can see status on github.
Those are good ideas! We made a discussion board where people can request/upvote features https://community.commotion.page/f/product-roadmap so hopefully that helps. I think stockpiling replies somewhere is something I'm gonna start doing right away