How serious is the threat of deflation

How serious is the threat of deflation? Bill Gross seems to think it's a real concern. It's kind of ironic, since Gross was absolutely wrong about inflation concerns back in the early days of QE, while at PIMCO. Now he's all for money printing to stave off deflation. At least it seems, he's learned his lesson. Gross says money programs from central banks aren't enough and money spending needs to come from the government. Of course, fiscal stimulus is what many economists have been calling for since the start of the recession. Unfortunately, politics has made it nearly impossible, at least in the US and Europe (where fiscal spending is needed the most). Perhaps the investors in Gross' new fund at Janus Capital will have the success they weren't finding at PIMCO. (VIEW LINK)