Android (operating system) and rival Linux mobile operating systems that were in development. These established players were skeptical: Nokia was quoted as saying "we don't see this as a threat," and a member of Microsoft's Windows Mobile team stated "I don't understand the impact that they are going to have." Since then Android has grown to become the most widely used smartphone operating system and "one of the fastest mobile experiences available". Reviewers have highlighted the open-source nature of the operating system as one of its defining strengths, allowing companies such as Nokia (Nokia X family), Amazon (Kindle Fire), Barnes & Noble (Nook),
Usage share of operating systems down to 72.76% and Chrome OS at 3.33%, plus traditional Linux at 1.46%. There is little openly published information on the device shipments of desktop and laptop computers. Gartner publishes estimates, but the way the estimates are calculated is not openly published. Another source of market share of various operating systems is StatCounter basing its estimate on web use (although this may not be very accurate). Also, sales may overstate usage. Most computers are sold with a pre-installed operating system (OS); some users replace that OS with a different one due to personal preference, or install another OS alongside it