The world of smartphones - and their spin-offs, tablets - is a fickle one, with entire empires collapsing in the blink of an eye.
A few years ago Nokia ruled the smartphone roost and Windows Mobile was a big hitter; today, Nokia's gambling an incredible £80 million to promote its forthcoming Windows Phone handsets.
As Chris Smith explains, the campaign is crucial not just to Nokia, but to Microsoft too.
"Nokia needs a strong software partner after years of persisting with Symbian sent the company into the smartphone abyss," he writes, "while Microsoft needs a high-profile hardware manufacturer that isn't also offering Android phones."
We like Windows Phone a great deal, but good reviews don't seem to have translated into big sales. Even Steve Ballmer admits that Windows Phone hasn't been quite as big a deal as Microsoft might have hoped.
Speaking at the company's Worldwide Partner Conference, Ballmer said: "We've gone from very small to very small". Estimates suggest that Microsoft's phone operating system has only picked up 1% of the market, with sales dwarfed by Apple's iOS and Google's Android.
What about MeeGo? (again)
Windows Phone isn't Nokia's only smartphone OS: it also has MeeGo, which proudly powers exactly one Nokia device. When the best thing a firm can say about its OS is a promise to support one device for years, it's clear that the platform isn't a top priority.
MeeGo may live on in other devices, such as tablets - Microsoft is adamant that Windows Phone is not for tablets - but its days as a smartphone operating system appear to have ended rather prematurely.
So which OSes are next for the glue factory? RIM's BlackBerry PlayBook suffered from embarrassing publicity when O2 decided not to stock it, citing "issues with the end to end user experience" that appear to include a distinct lack of tablet apps for its Tablet OS.
HP's webOS appears to be healthy - the firm is apparently discussing licensing deals with other manufacturers. Mind you, there's a big difference between firms "expressing interest" and plumping for a new and relatively untried OS. And especially when that OS currently delivers "sluggish" performance, a poorly stocked AppCatalog and what our HP TouchPad review describes as "death by 1,000 paper cuts".
Can iOS and Android be touched?
The challenge for webOS is to do something different from iOS and Android, two platforms whose future isn't in any doubt. The sole webOS tablet, the HP Touchpad, "is less polished than the iPad, with a smaller range of impressive third-party apps," we found.
"Yes, it's got features that the iPad lacks, but so do the Android tablets, and they have a bigger app selection too... HP webOS is a very well thought out operating system, [but] would you buy it over the others? We're not sure many people will find an answer to that question."
The question applies equally to hardware manufacturers: why buy webOS over Android, when even Android is struggling to match Apple's enormous catalogue of apps?
As Gary Marshall reports, the forthcoming Android 4.0 - codenamed Ice Cream Sandwich - is precision-targeted at app developers, with a unified codebase enabling them to code for every kind of device and a host of new APIs (Application Programming Interfaces) to make app development easier.
As we said earlier, the world of smartphones and tablets is a fickle one - but it's safe to say that unless Google or Apple does something amazingly, incredibly stupid, mobile devices will be dominated by iOS and Android for the foreseeable future.
It'll be interesting to see what, if anything, webOS, the BlackBerry Tablet OS and Windows 8 can do to dent that.
Liked this? Then check out Why Microsoft's tablet strategy is flawed
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