[senecaso]

I was thinking more along the lines of a public dialog, where a user could post a comment like "This is a great idea! However, if you could make it do X and Y, it would be even better!"

Getting access to people's contact information would be useful at a later point in the process, but early on I think immediate feedback would be the most beneficial. Even something along the lines of a HN thread like this one would be enough engagement at first. In fact, perhaps that is even sufficient :)

[leobg]

Right. This should be possible without necessarily giving up one's privacy.

I wouldn't want a public dialogue. Because that would signal public interest in the idea to outsiders. This is something that I imagine people posting an idea want to avoid, because they don't want to attract competition if the idea turns out to be a good one.

But it would be easy to have a two-way-conversation with the creator. So user john can post a message to idea owner thomas. Thomas can even reply, and they can write back and forth. But john will ever only see his own conversation with thomas, and never those that thomas might have with others, such as ben or lucy.

This is actually one of the major reasons I made the site, even though there's Hacker News. If my idea got traction on HN, it would attract more and more attention, and I'd have no way of pulling it from the site. Public interest in the idea would be documented for everyone to see, forever.