Of course, the Internet is many things to many people. It is a way to communicate and stay in touch with friends far away, it is a way to network and make new friends, it is a place to play games, to adopt alternate personalities and indulge in role play, it is useful for finding information,
1st, it would be dedicated to finding solutions to the problems which plague mankind. Global warming, overpopulation, war, poverty, hunger, religious extremism, rights for minority groups and the high price of living would all be fair topics for discussion, among others.
Visions of Utopia May Vary
It would start with an open board, where anybody could post anything. The moderators job, however, would be different than on most sites. On most sites, they’re just there to delete offensive comments. On my site, their job would be to look for those comments which actually make a point (not just saying Hooray for our side), a suggestion for how things could be improved, some problem could be solved. Those comments would move through to a 2nd level.
Comments on the 2nd level threads would be screened. They would have to be on topic, contain reasonable arguments without logical fallacies, and be under 300 words or so. (If you have more to say, provide a link) In this way, the ideas could actually be debated to one of 3 possible conclusions. Voted up by consensus, voted down by consensus, or amended, in which case the process begins again on a new thread.
Threads stay active only until a conclusion is reached. Then, the debate switches to methods of implementation.
In a way, a site like that would be creating a platform for a worldwide people’s party. Because I think most people would really like the same things – a nice home, 3 squares a day, economic security, freedom, good health care, clean air and drinking water, high speed rail and at least two joints a day. We just don’t all agree on how to get there from the dysfunctional mess we find ourselves in today. But, intelligent people could talk it out.
www.gurukalehuru.com 
Check out http://slashdot.org. It’s not perfect, but it has many of the features you mention. The stuff worth reading tends to rise to the top, though not always, of course.
Even though we almost never discuss who Emma Watson is dating, you still see a few posts complaining that “This isn’t news!” Meh.
Thanks! I’ll check it out.