Every time I tell someone about OpenStreetMap, they inevitably ask "Why not use Google Maps?". From a practical standpoint, it's a reasonable question, but ultimately this is not just a matter of practicality, but of what kind of society we want to live in. In the 1800s, people were struggling with time, not how much of it they had, but what time it was.
Google started the ball rolling with apps, and OnLive lit a fire under this with games. As we move into 2012, more and more of what we access will be hosted.
Already, movies are streamed rather than downloaded, and it won't be long until most of our applications exist on the Internet and don't run locally. I expect a big push in this direction in 2012.
HTML5 -- the fifth iteration of the HTML standard -- and it lets developers create richer, more interactive applications than ever.
Why does this matter? As developers tire of building applications for every operating system out there -- from Android to iOS to Windows Phone and beyond -- HTML5 offers the opportunity to build an app once and have it work everywhere.
New input methods will be the dominant trend of 2012. Tablet computers such as the iPad might seem like a nice alternative to desktop and laptop computers, but I believe they're more than that: They're replacements. Just as the command line (remember that?) gave way to graphical user interfaces, so the mouse will be superseded by touchscreens.