I could see this coming and when the iPad went ballistic I knew it. Smartphones, tablets and other app-enabled devices will overtake PC shipments in the next 18 months, an event that may signify the end of the PC-centric era, market research firm IDC said. IDC said worldwide shipments this year of app-enabled devices, which include smartphones and media tablets such as the iPad, will reach 284 million. In 2011, makers will ship 377 million of these devices, and in 2012, the number will reach 462 million shipments, exceeding PC shipments. In 2012, there will be 448 million PC shipments. One shipment equals one device. PC sales will continue to climb, but will no longer rule.