Mark Twain would have been amused by the remarks of new Apple Inc. (Nasdaq: AAPL) CEO Tim Cook last week when he announced the "post-PC era."

Cook was ballyhooing the company’s latest iPad before devotees, of course. But he may have been insulting his shareholders. Truth is, only about 20 percent of Apple’s revenue comes from the iPad.

As Twain observed after reading his obituary, "The report of my death was an exaggeration."

No doubt, the iPad family — with more than 55 million units sold, is a "disruptive" technology — as defined by former Harvard Business School Dean Clayton M. Christensen. But it wasn’t the first in the tablet category.

Amazon.com Inc. (Nasdaq: AMZN) has been selling Kindle e-readers for years, and Barnes & Noble Inc. (NYSE: BKS) has done nicely with the Nook. Analysts at Forrester Research Inc. (Nasdaq: FORR) estimate Amazon shipped 5.5 million Kindle Fires last quarter, while Barnes & Noble sold 3 million Nooks.

Source: http://www.ibtimes.com/articles/312412/20120311/pc-tablet-ipad-apple-ibm-hp-laptop.htm