Amazon fans look down at their crotches and express awe and astonishment at whatever they're seeing in this mysterious film released by Amazon on YouTube Wednesday. There are a few hints at what it could be. It might possibly be an eye-tracking feature for a new Kindle ("It moves with me," says one customer), or, as rumors have long swirled, Amazon is close to unveiling its own-brand smartphone. It could also be a 3D screen -- which, as the Journal has reported, the company is developing for its Kindles and other devices too. A link on the YouTube film leads to a site where you can request an invite for Amazon's event on June 18, where all will be revealed.