A couple of solutions seem to try to address this: productboard, ProductPlan, airfocus... There are a couple of more tools to manage feature requests and communicate with customers around them.

I'm also curious to see how these tools will evolve. I haven't used any of them, but from an external POV Productboard seems to have the strongest focus on managing customer feedback and generating product insights, rather than just building and communicating a roadmap.

> Interestingly there is no product on the markt to collect feature ideas and classify them.

As a dev who's been on HN since 2008, I'd be remiss not to "market more" and plug what I've been working on here! I started Savio (https://www.savio.io) specifically to help B2B SaaS teams collect and classify customer feature requests to help inform prioritization.

It was a pain I've felt for over a decade. So after we sold our last company, one of my co-founders and I decided to solve this problem once and for all.

Here's a guide I wrote that lays out everything me and my co-founder know about tracking and using customer feature requests to drive prioritization (we have 40+ combined years of experience PMing and coding at co's like Microsoft, ESPN, 7 startups, and about a dozen consulting clients).

https://www.savio.io/blog/how-to-track-customer-feedback/

That's exactly what https://www.productboard.com/ does.

I doubt that this will help you deciding what to build though

I listened to a podcast with the founder recently and it sounds like they are trying to go more into that direction, which would be a key differentiator if they manage to do it (rather than just providing a tool to manage feedback/build roadmaps). In terms of "deciding what to build", user research tools such as https://dovetailapp.com/ and https://consider.ly/ might be interesting as well. They are just not positioning themselves towards Product Managers (yet).

Aha.io might surprise you

Check out featmap.com, it's a user story mapping tool.