Google laughs off the 'Osborne Effect'
I'm guessing not many folks at Google are old enough to remember Adam Osborne (though CEO Eric Schmidt is one). Back in the '80s Osborne's namesake Osborne Computer Corp. introduced the first popular portable computer.
In those days, a 25-pound luggable qualified as portable and the Osborne sold like hotcakes.
But It was also one of the great early flameouts of the PC era. Osborne made the mistake of pre-announcing a successor machine months before it could be delivered and sales of its existing line dried up sending the company into a tailspin it never recovered from. The preannouncement, while according to some accounts wasn't the main cause of Osborne's demise, became known as the "[Osborne Effect](http://en.wikipedia.org/wiki/Osborne_effect)," a cautionary tale for any company considering pre-announcing products before they're available.
But there have been many significance pre-announcements of new tech products. The famously secretive Apple previewed the iPhone six months ahead of delivery. The company said the details would have come out in its FCC filing so it figured better to spill the beans on its own terms. More importantly, Apple didn't have to worry about dampening sales since the iPhone was its first foray in the phone market.