Why do we need editors?

It's a provocative question to pose publicly if you're a journalist, and that's exactly what GigaOM's Mathew Ingram did today on Twitter:

He sparked an interesting discussion about the value of editing, how errors spread, and the ability of journalists to offer adequate correction. It's a timely discussion, given the recent announcement that the Denver Post is eliminating its copy desk, and what that means for the business. Here are some of the highlights of the conversation.