United Stock Plunge: How It Happened

United A six-year-old Chicago Tribune story about United Airlines entering bankruptcy caused a massive sell off of the company's stock, resulting in the stock losing 75% of its value before trading was halted. Here's what happened.

- The six-year-old story received enough hits for it to appear in the "most viewed" list in the business section of the Sun Sentinel sometime between 1:00:34 a.m. and 1:36:03 a.m. Sunday Eastern time.

- Seeing the "most viewed" list updated, Google's bot crawled the page and picked up the story. Since the bot couldn't determine when the story was published, it put its own time stamp on the article: Sept 8, 2008.

- By 1:39 a.m. Sunday, the story appears in Google News searches.

- Traffic from Google kept the outdated news story in the "most viewed" list.

- Researcher at Income Securities Advisors saw the article in the Sun Sentinel's "most viewed" list and posted the news as current in Bloomberg's news service.

- Sell off began.

Read more over at the Chicago Tribune.