Jet.com went live today with plenty of buzz, but its long-term viability is questionable. The well-funded e-commerce website offers consumers an alternative to Amazon for seemingly all of their online shopping needs. Industry watchers are fascinated with the new player for two chief reasons. First, there's Jet.com founder Marc Lore, who also launched Quidsi, the parent company of Diapers.com and Soap.com, before selling it for $545 million to Amazon in 2010. The second reason centers on whether or not his business model can survive over the long haul.