The misc mailing list is the (strangely named) main one: https://groups.google.com/a/dartlang.org/group/misc/topics. Join and fire away.

> I'm not too keen on using underscore-starting identifiers to determine what is public and what is private.

That's also been discussed. It has more going for it than may be at first apparent, but it has detractors too.

_ for enforcing encapsulation is great, probably the one thing I've seen in dart that's exciting. simple way of giving an existing naming convention significance and cutting down on character overhead. i could see a whole line of languages expand on this idea.

The homepage links to this: http://www.dartlang.org/support/index.html.