Taking a loss on something to establish or maintain a dominant market position is predatory pricing. In the short run, that may benefit consumers, but it won’t in the long run.

(UPDATE: I’ve made several copy edits to fix tenses in the opening few paragraphs)

Ryan Chittum is a former Wall Street Journal reporter, and deputy editor of The Audit, CJR's business section. If you see notable business journalism, give him a heads-up at rc2538@columbia.edu.