Windows Mobile already had issues with general clunkiness and sluggish performance, but with the emergence of the iPhone and Android, the mobile operating system's problems were only amplified and customers started looking elsewhere.

To Microsoft's credit, the company acknowledged that things weren't working and rather than try to revamp the current system, it started over from scratch and thus, Windows Phone 7 was born.

Introduced in February 2010 at Mobile World Congress, Windows Phone 7 showed off a fresh, fun, and functional OS that got the tech world excited again.

The first devices finally debuted in November, with mostly positive reviews of the OS. Admittedly, Windows Phone 7 is missing some core features, but an update, as well as CDMA handsets, are planned for early 2011. We're looking forward to seeing more from Microsoft and Windows Phone 7 in the new year.

BlackBerry maker Research In Motion also came out with an overhaul of its mobile operating system.

Previewed at WES 2010 in April, BlackBerry OS 6 made its official debut in August on the RIM BlackBerry Torch. The software featured a more touch-oriented interface, enhanced multimedia features, and, finally, an improved Web browser. It was a nice evolution of BlackBerry OS but nothing revolutionary like Windows Phone 7. The fact that the Torch was underwhelming in the hardware department didn't really help OS 6 make a big splash.

Still, BlackBerrys enjoy great popularity, whether it be for the enterprise-friendly security features or loyal users of BlackBerry Messenger, and RIM has continued to churn out new devices, such as the BlackBerry Style and BlackBerry Pearl 3G. RIM will also release its first tablet, the BlackBerry PlayBook, in early 2011.

As has become tradition, Apple CEO Steve Jobs unveiled the new iPhone in June. Among the touted features of the iPhone 4 was a wraparound antenna, but this soon became its worst feature.

Soon after the iPhone 4 went on sale, some customers complained that touching the seams of the antenna band weakened or completely dropped the phone's reception. Though the problem didn't affect everyone, there were enough reports to make it a major headline, and our tests did indeed show that covering the antenna affected the phone's performance.

Initially, Apple remained mum on the issue and then later blamed the user and a software flaw, but as lawsuits were filed and demands for a recall were made, Apple finally acknowledged there was a problem.

Just a little over a month after the iPhone's launch, Jobs took to the stage again and said though the situation's been blown out of proportion and that attenuation affects its competitors, too, Apple would offer free bumpers to iPhone 4 customers.

Not Apple's best moment, but hey, at least it gave some accessory companies the opportunity to come up with some clever fixes for the iPhone 4.

Though there's debate over what can truly be called 4G and the different technologies can be confusing, the fact is that the next generation of wireless technology is here, which for you as the customer means faster data speeds on your handsets.

Sprint, with its partnership with Clearwire, got things started this year with the launch of the first 4G handset in the U.S., the HTC Evo 4G, and followed that up with a second device, the Samsung Epic 4G.

T-Mobile also got in on the action. As CNET News' Maggie Reardon points out in her article here, the carrier's HSPA+ network doesn't meet the technical definition of 4G, but it is an extension of its 3G network and we've experienced and have been impressed by the faster data speeds on its "4G" handsets, including the T-Mobile MyTouch 4G and T-Mobile G2.

Regardless of whether it fits the definition or not, T-Mobile is taking the 4G name and running with it, as it has launched an aggressive ad campaign to get the word out.

Most recently, Verizon announced that it will flip the switch on its 4G LTE network December 5 to 38 cities and 60 airports around the country. Though the carrier will only  launch with two USB modems, it plans to have consumer-oriented smartphones by mid-2011, which is also when AT&T plans to launch its 4G LTE network.

Taking a page from Verizon's book, when the carrier said "whether you call it 4G or chicken soup," 4G and the next-gen of wireless technology is here.

Despite rave reviews of the Palm Pre and WebOS in 2009, tough times fell on Palm, which saw company earnings slip in 2010, and soon there was talk of a buyout.

Of all the companies that were thrown out as possible suitors--HTC, Dell, and Acer, among others--HP wasn't considered a front-runner, yet on April 28, the companies announced that HP would buy Palm for $1.2 billion. The deal was completed in July.

Since then, HP Palm has released WebOS 2.0 and the Palm Pre 2, though we haven't seen anything drastically new in the hardware department. In addition to smartphones, HP said it plans to use WebOS for tablets and Web-connected printers, so we'll see these all in 2011. 

More than smartphones, HP said it acquired Palm for its portfolio of intellectual property.

Really, 2010 could be called the year of Android. Although there seems to be a study released every week on mobile OS marketshare and popularity, one thing is certain: Android has made significant gains in both.

And it's not hard to see why. Android phones are available from all four major carriers in the U.S., as well as smaller regional carriers, and there are numerous models to choose from. We're also now seeing models with lower price points.

So far in 2010, we've reviewed close to 50 Android phones; compare that with the 9 models we reviewed in 2009, and you can see how much Android has exploded.

Of course, it hasn't been all sunshine and roses. With all those devices, there's been a problem with Android fragmentation and a lot of passing off of responsibility when issues occur. Hopefully, 2011 will see a resolution to the problem, while still seeing continued variety in design and price point.