Sony has at long last confirmed rumors of the PSPGo's demise. The handheld console was poorly received by the public for its lack of proprietary support for Sony's own UMD discs, making most pre-existing titles for the PSP inaccessible to owners of the newer device.
According to Sony, the PSPGo has been scrapped because the publisher intends to focus its full efforts on the upcoming NGP, which is set to replace regular PSPs and be a serious contender against the Nintendo 3DS.
There was little point for Sony to release a new iteration of the PSP without offering existing UMD support or meaningful upgrades, so it's doubtful that anyone will even care about the fact that it will no longer be sold.