Unless you were under a rock, it was virtually impossible to miss today’s unveiling of the Apple iPad. Nonetheless, people wanted to make sure their friends knew about it too, and have been retweeting, sharing, and email forwarding stories about the new device in droves.Clearspring, whose AddThis sharing widget is viewed more than 50 billion times per month, tells us that shares about Apple-related news are up more than 600% today. The massive volume spike is illustrated in the chart ...