Twitter’s IPO Filing Implies $12.8 Billion Value Amid Growth

A user checks a Twitter feed on a smartphone in this arranged photograph taken in London, U.K., on Friday, Oct. 4, 2013. Twitter Inc.’s initial public offering documents suggested a valuation of $12.8 billion for the microblogging service, underscoring the seven-year rise of a still unprofitable company that has helped revolutionize how people share information. Photographer: Chris Ratcliffe/Bloomberg via Getty Images