Windows 7

Microsoft on Friday announced that it has sold over 350 million licenses of Windows 7 in the past 18 months. The milestone points to a momentum in the adoption of Windows 7, but Microsoft didn't break down the numbers into how many copies shipped with new PCs or are upgrades.

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Despite impressive growth, Windows 7 is second (with 24 percent) only to its older sibling, Windows XP, which still holds around 55 percent of the market. But Windows 7 could on track to become the most popular operating system if Microsoft continues to sell at this rate. Alex Wilhelm calculated for The Next Web that Microsoft sold over the past 18 months 450 copies of Windows 7 per minute. So to be more exact, Windows 7 will eclipse XP in 12 to 15 months, according to an ArsTechnica estimate.

"Analyst firms like IDC estimate that more than 90% of businesses are currently in progress with their Windows 7 migrations," wrote Microsoft's Brandon LeBlanc on the Windows Team Blog. This migration allows businesses to save around $140 per PC per year, LeBlanc claimed. "The momentum we've seen and continue to see with Windows 7 is incredible."

Windows 7 is doing particularly well compared to Vista, which only sold 180 million licenses in 18 months. GeekWire estimates that put in the context of license sales versus total PC shipments, Windows 7 beats Vista hands-down. Based on IDC data, Windows 7 licenses equate to 68 percent (out of 517 million shipments) of overall PC sales in 18 months, while Vista only performed 45 percent (out of 400 million shipments) at the time.

Expected late next year, Windows 8 will be Microsoft's next OS iteration. Details are starting to trickle on what sort of new features will be available, such as immersive browsing, a PDF reader, an app store, ribbon toolbars, and a lock screen. Windows 8 is also said to bridge the gap between desktops and tablets with a touch-optimized interface.