Gianfranco Lanci's departure from Acer last month came as a bit of a surprise, but looking at some fresh PC shipment data from the IDC, we can now understand why it had to happen. In Q1 of 2011, Acer suffered a precipitous 42.1 percent drop in PC shipments to the United States, falling from 2.3 million units in the first quarter of 2010 to 1.3 million in the first three months of this year. That's matched by a global downturn of 15.8 percent for the company's computer business, taking its market share from 12.9 percent down to 11.2. A percentage point and a half might not seem like much, but in the high stakes business of selling high volumes of devices with low profit margins, that can clearly make the difference between winning and losing, between living and dying (as a CEO). On a happier note, Lenovo surged upwards by 16.3 percent globally amid a market that shrunk a little overall. The IDC -- whose numbers are considered preliminary until companies confirm them in their quarterly financial reports -- identifies Acer's exposure to the shrinking interest in netbooks as the chief reason why it's now having to reorganize itself. That overhaul is already underway with a new logo and some attractively priced tablets, but it's likely to be a while before Acer gets back to challenging HP for world domination.

Update: Gartner has dropped its figures for the first quarter as well, and while it doesn't see Acer losing out quite so badly in the US (minus 24.9 percent year-on-year), it agrees on its worldwide market struggles, placing its decrease in shipments at 12.2 percent.