A netbook is a small and inexpensive laptop designed primarily as a means of accessing the Internet. Netbooks were sold from 2007 until around 2013, when the widespread advent of smartphones eclipsed their popularity. Netbooks generally had lower-end hardware specifications than consumer laptops of the time, being primarily intended as clients for Internet services. While netbook has fallen out of use, these machines evolved into other products including Google's Chromebook, and mobile devices, particularly tablet computers, often running mobile operating systems such as iOS or Android. At their inception in late 2007, as smaller-than-typical laptop computers optimized for low weight and low cost, netbooks began appearing without certain then-standard laptop features (such as an optical drive), and with less computing power than in full-sized laptops. Later netbooks ranged in size from below 5" screen diagonal to 12". A typical weight was (). Often significantly less expensive than other laptops, by mid-2009, netbooks were often offered by some wireless data carriers "free of charge", with an extended service-contract purchase. Soon after their appearance, netbooks grew in size and features, and converged with smaller laptops and subnotebooks. By August 2009, when comparing two Dell models, one marketed as a netbook and the other as a conventional laptop, CNET called netbooks "nothing more than smaller, cheaper notebooks", noting: "the specs are so similar that the average shopper would likely be confused as to why one is better than the other", and "the only conclusion is that there really is no distinction between the devices". At their peak, the easy portability of netbooks, and expanding Internet access, gave them a significant portion of the laptop computer market. To protect sales of their more lucrative laptops, manufacturers soon imposed constraints on the hardware of their netbooks, which had the unintended effect of pushing netbooks into a market niche where they had few distinctive advantages over traditional laptops or the newly emerging tablet computer. By 2011, the increasing popularity of tablet computers (particularly the iPad), which offered a different form factor, but with improved computing capabilities and lower production cost, had led to declining sales of budget netbooks. Meanwhile, the emergence of ultra-light laptops with the dimensions and hardware specifications of high-end laptops, most notably the MacBook Air, allowed fewer sacrifices for a lightweight laptop, at a considerably higher price, eating into sales of high-end netbooks. Soon after, Intel promoted the "Ultrabook" as a new high-mobility