> A news site that tried to include "everything that happened today" is useless,That pretty much describes newspapers on in Internet age, though. I can trivially access newspaper websites across the US and much of the world, and see everything that happened recently that passes the local newspaper's bar for notability, which for a small town paper is going to be lower than for national news (as it should be).
We've developed (or should I say Google News and other sites have developed) systems to take filter the firehose in some fashion, and if WikiTribune started off simply linking to other people's reports on everything that happened every day, they would quickly be forced to develop their own filtering system.
Given Wikipedia's charitable mission, I imagine the system will be open in some fashion. While Wikipedia's committee holds an undue amount of power compared to random IP addresses editing that want to edit Wikipedia, think about how much power is bestowed upon the members of the board of the six companies that own 90% of the news media.
Right now, it takes a non-profit and their staff dedicated wholly to an issue (eg http://www.gunviolencearchive.org ) to offer data which a reporter can draw from, if not they are forced to do it themselves. I hope to see WikiTribune expose data and metadata about news stories that can then be plotted on a timeline to make it easier for reporters to see connections between stories, and allow to share those with commentary.