RIM has quietly cut its sales expectations for the BlackBerry PlayBook after its disappointing sales from the spring, those in the supply business said Wednesday. It had planned for as many as 2.4 million of the tablets in its summer quarter but had now pared that back to between 800,000 and 900,000 units. Digitimes claimed RIM had an optimistic prediction of 2.4 million PlayBooks for its most recent quarter but, at 500,000 units, wasn't going to reach its next goal.