Not quite crowdsourcing in any true sense, yet written and rewritten by hundreds, lacking in original sources and devoid of original reporting, in fact not quite journalism at all, nevertheless Wikipedia consistently presented the best overall story on the Virginia Tech shootings. With a buried lead and no hint of an inverted-pyramid story structure, requiring more than 6th-grade English but consistent with journalism's revered principles of accuracy, verifiability, and neutral point-of-view, this Wikipedia entry and the accompanying one for Cho Seunghui present the single-most comprehensive, accurate, deepest, and up-to-date articles on the subject.
Nobody can read nor follow all 3990-plus articles from Google News on this. Instead at Wikipedia, read especially the Talk pages and follow the editorial decisions and arguments for what was left out, and see the rationales and judgment used like in any newsroom.
I rarely give superlative recommendations, and i'm not sure what this means for citizen journalism, but after having followed the stories, the Wikipedia articles and their Talk pages, and even contributing to them, since events broke i have found no better single authority. See for yourself.
(Maybe you've followed this way too much like i have and don't need to read more. I might not have, had i not first heard "Asian". Finally though, voices such as Robert Siegel on National Public Radio All Things Considered, the Washington Post, and yes Wikipedia, get the perspective.)