Take a look at today’s Wikipedia entry on today’s Mumbai terrorist attacks — a comprehensive and valuable addition to the breaking news we’re getting from TV and other sources. There are two fundamental elements to note: the rapid updating and the long list of links at the bottom.
No, we can’t fully trust what we see here, because Wikipedia is susceptible to tampering. And yes, it relies on traditional journalism sources for much of the information. But this resource is immensely valuable as a backgrounder.
Also: Once I wondered whether Wikinews would be a valuable journalism source. It’s increasingly clear that Wikipedia itself is vastly more important when it comes to major events. Compare the Wikipedia entry above to the Wikinews Mumbai entry, and you’ll see why.