Crowd-sourcing content is one aspect, but I'm very much looking forward to "subscribing" to a story and getting only updates after that -- as short as possible, whether they be corrections, links to related stories, or truly new information. I can fit a lot more news into my day if I don't have to hear/read the same context/intro information each time there's an update.
Less important to me is a "ask the author" system, by which readers can suggest directions for investigative journalists to take: how is this incident related to previous ones, what's the political context for this, does anyone have any proposed solutions to the problem, has anything changed since this story was posted 6 months ago, etc. I don't necessarily want to read opinions from fellow readers, nor post my own "facts" as a citizen-journalist, I just want to prod journalists into doing more of what they already do well.