Cloud? Tablet computing? Android? Social media? Scrum? Lawsuits? It’s hard, really hard, to characterize the year that is about to conclude.

Looking back at 2010, some of the biggest news stories were regarding Java—yet it was not the Year of Java. The completion of Oracle’s acquisition of Sun Microsystems brought up a lot of talk about MySQL and Java, but beyond some progress around the OpenJDK, not much happened.

Microsoft, a perennial newsmaker, advanced many of its tools and platforms, with significant upgrades offered to Visual Studio, Windows, SQL Server and SharePoint. While those delighted customers, none of those bits represented a game-changer. Perhaps Windows Phone 7 will ring the gong. Perhaps not.

We could call 2010 the Year of the Cloud. Over the past 12 months, many development organizations moved from studying cloud technology to actually using it, though in most cases that we’ve seen, cloud projects are still in the pilot phase. With fast-evolving offerings from Amazon, Google and Salesforce.com, and Microsoft’s release of Windows Azure and SQL Azure, there’s no doubt that 2010 is when the cloud changed from vaporware to reality. The impact, though, is marginal.

Maybe 2010 was the Year of Scrum, or at the very least the Year of Agile. Certainly there were few conversations with industry vendors that didn’t start with the word “agile,” as seemingly every product and service was retooled (or at least remarketed) to promote agility. Of the agile methodologies discussed, Scrum received the lion’s share of the conversation. Yes, 2010 was when agile went mainstream.

Social media? It was all Facebook, all the time, except for when you were talking about Twitter. Blogs are, like, so 2009; if Google is the new Microsoft, then Facebook is the new Google. What’s the impact of all this social media hyperbole on the enterprise? Hard to assess if it matters.

Lawsuits? Some years are dominated by the courtroom, and 2010 had its share of breathless litigation. Oracle vs. SAP, Oracle vs. Google, everyone vs. Apple; patents and intellectual property are huge issues, and due to the complexity and confusion around the law, lawsuits are here to stay. None of them, however, appeared to be a show-stopper.

Speaking of Google, this may have been the Year of the Open-Source Mobile Operating System. Android 2.2 came out strong and found lots of uptake from carriers, handset makers, software developers and consumers—many of whom chafed under Apple’s tough rules, closed platforms, exclusive partnerships and high prices. With Android, however, we’re still seeing the early stages of its evolution.

If one must pick a single touchstone, let’s call 2010 the Year of the Tablet. Or, more specifically, the Year of the iPad, since Apple’s offering kicked the stuffing out of all the competition. Not only did iPad sell better than industry observers predicted, but it sold broadly, affecting both consumers and business users. In fact, some analysts have revised their laptop sales projections downward due to the iPad’s unexpected success.

Thanks to the iPad (and the iPhone), we now have a new category of developer: app developer, joining those who build desktop, server, embedded and Web software. Equally important is the App Store, a strong new vehicle for software distribution in both the mobile and cloud markets.

Next year may not be the Year of the iPad. Android competitors are coming on strong with their many tablet platforms, and traditional notebook computers are growing smaller. But if there was a single big change in the year, it was that, thanks to the iPad, the tablet computer is the first significant new computing platform that we’ve seen in many years.

Can’t wait to see what comes next.