When it comes to Gartner, they've been wrong before. As to the cloud, there's an interesting post here (not claiming he's accurate or not):
http://gigaom.com/cloud/gartner-gets-it-wrong-with-cloud-quadrant/

From your link, it will be interesting (around 2015-2016) to see who called it right:
The prediction is in line with both Ovum and IDC, with ABI Research the lone outlier, predicting a less than 10% market share for Windows phone 7 in 2016.

I'd like to know how much, if anything, MSFT (or any other provider) is paying any of those or if they benefit in anyway from MSFT.... that won't necessarily change the accuracy, but let's face it, predictions sometimes have a way of coming true by virtue of the prediction itself. It just is interesting that people will immediately discount industry funded research, but not when it comes to IT predictions.

>WebOS doesn't even register on predictions I've seen. For example, http://wmpoweruser.com/gartner-predicts-windows-phone-7-will-overtake-blackberry-in-2013-overtake-iphone-in-2015/?utm_source=twitterfeed&utm_medium=twitter
>
>>Uh, you mean WebOS as the 3rd competitor, right? <g> Seriously, 6% of the market isn't a competitor.