With an estimated 8.5 million units sold to date, the iPad is now the best-selling tech gadget in history, according to Colin McGranahan of Bernstein Research. In a note to clients — as reported by “InformationWeek” (http://www.informationweek.com/news/storage/portable/showArticle.jhtml?articleID=227700347&itc=ref-true) — he called the Apple tablet “a runaway success of unprecedented proportion.”

Apple sold three million units of the iPad in its first 80 days on the market. Third quarter sales were in the range of 4.5 million units, and overall it’s estimated that Apple has shipped about 8.5 million iPads to date worldwide.