I like the idea, but I'm not sure people will necessarily know what they want to read about. Take, for example, a disaster, people would want to know about it as soon as possible. You don't want to wait until someone votes on the topic before writing about it.

So I'd modify your idea a bit -- have many short snippets about rumors/events that quickly introduces a subject, to build interest, and will be free to everyone. Then have followup stories that will be voted upon.