Many (myself included) have assumed that smart phones are poised to take over the computing market and surpass PCs as the primary way in which people around the world consume computing resources, whether they're local applications or web-based/cloud services. It turns out that it's more accurate to say that "phones" (i.e. not just smart phones) are making this transition. And it's happening quickly.
This information comes from a Forbes article about Microsoft Office running on smart phones. This article has some interesting speculation specific to Microsoft Office--primarily that the author believes "Microsoft may be looking to make Office compatible with all smart phones to position itself favorably for the large smart phone market--and some data about how important Office is to Microsoft's stock.
I'm more interested in the data around smart phone penetration.
By 2013, the installed base of smart phones is expected to be around 1.32 billion, compared to the PC installed base of 1.78 billion.
The total mobile phone installed base (smart phones and feature phones) will be around 1.82 billion and hence will exceed the PC installed base by 2013.
We expect that the smart phone installed base will exceed the PC installed base before 2020.
Of course, the smart phone market doesn't need to exceed the size of the PC market to be more interesting, dynamic, exciting, news worthy, or whatever else. Witness Apple's success in various markets, almost none of which it actually dominates. So while it may be a decade (or more) before smart phones are more prevalent than PCs out in the real world, assuming this does happen, it's likely/possible that PCs will have become less interesting, if you will, well before that.