Nothing illustrates what makes the tech business both fascinating and frustrating as well as the rise of Facebook. The social-networking site crossed the 500 million-user mark and debuted numerous features, such as an upgraded e-mail service and options to share your location with friends and get discounts from nearby retailers. But it also spent much of the year infuriating users with privacy changes that exposed more of their data and were confusing or impossible to undo. The simpler privacy interface it launched in May should help, but it won't if this company (on whose board of directors Washington Post Co. Chairman Donald E. Graham sits) again forgets that its users don't all operate at start-up speeds. Other social networks had a smoother road. Twitter offered its growing user base a more reliable service and a busier but more useful interface, while Foursquare had users checking into such far-off locations as the international space station. You can't write the story of any of these sites without noting how smartphones have allowed their users to connect from so many places. Apple's iPhone 4 led that pack in 2010, but Google's Android operating system improved at a faster pace and didn't require its users to sign up with only one carrier - even if some of the carriers selling Android phones showed a serious lack of taste in their tweaks to Google's software. I probably devoted more column inches to smartphones than to any other sort of hardware, and with good reason: This is the most exciting, fastest-moving part of the electronics industry. (Many of my articles and those of others covered the weird controversy over the iPhone 4's reception . More should have been devoted to Apple's arbitrary and unaccountable control over what goes in the iPhone's App Store.) Tablet computers aren't far behind, though. Apple's launch of the iPad in January redefined this market in a way that finally made the concept relevant to home users. Competitors took the hint and have begun rolling out devices that will never qualify as "iPad killers" but do earn the title of "iPad competitor." The success of the iPad and other tablets pushed down the price of the Kindle and other e-book readers. But Amazon's e-reader may need to drop below $100 and get a major screen upgrade to hold its place in the market. Both smartphones and tablets have further eroded the significance of traditional desktop and laptop computers. Sure, people still buy the things in massive numbers. But when you can get so much work and play done on a smartphone or tablet - or, for that matter, any other device with a browser that can run Web-based applications like Google Docs - why bother stressing out over your choice of one brand of computer? This trend has hurt Microsoft, the company that once benefited more than any other from the traditional computing market. Its biggest software shipment of the year, its Office 2010 productivity suite for its Windows operating system, was a yawner of a release. You'd think that this same shift would have made 2010 an unmitigated success for Google. But the firm, based in Mountain View, Calif., had a surprising series of flops. Its Buzz social-media service alienated users automatically enrolled in it, it gave up on selling its Nexus One Android phone directly to consumers and its new e-book store didn't live up to advance hype. Google's most painful failure must be its attempt to fuse Web video and subscription programming in its Google TV software. Uncooperative networks promptly sandbagged it by preventing Google TV devices like Logitech's Revue from playing shows off their Web sites. The transition of TV viewing from expensive, inflexible programming bundles will take longer than Google might hope. But it's happening - between the rise of such simpler devices as Apple's relaunched Apple TV and Roku's cheap, eponymous Web-media receivers, it's easier than ever to enjoy Internet video on a big screen. There's a reason, in other words, why "connected TV" has far more of a future than 3-D TV. Overall, things look better for tech users after a year's worth of change. But two threats could slow or halt much of this progress. One is the ability of Internet providers, especially wireless carriers, to block or impede services or applications they don't like. The government had a chance to write clear rules about "network neutrality" but, after months of indecision, wound up settling on limited, uncertain regulation. Another is a patent system that invites abuse by companies that, having won major patents years before, can then try to win the tort lottery by suing firms that have brought successful products to the market. 2011 looks promising, especially with the prospect of faster "4G" wireless across more of the country. But if you're looking for ways for things to go wrong, start with those issues - then remember that, just as in every other year, the tech business will continue to serve up its share of buggy 1.0 releases.