A huge market...

As of 2016 our world had a global population of 7,5 billion ... and 6,8 billion mobile phones in use !
Incredible - keeping in mind that the number of active subscribers stood at just 750 million in 2000, it increased in a bit over a decade by 900 %.

The annual shipment of new PDA' and Smartphones (i.e. internet-enabled handheld communication devices) alone crossed 1,25 billion in 2014, overtaking for the first time the global sales of PC's.

The share of smartphones grew from less than 1% of total mobile handsets shipped in 2002 to 5% in 2007 and over 20% in 2013 ... but accounts for over 50% of all airtime.

While Nokias Symbian was initially the most used OS (=Operation System / Betriebssystem) for high-end smartphones with an overwhelming 60% share in 2002, Symbian's worldwide share of this market, however, dropped to less than 39% in 2009 and is with under 1 % nowadays almost nonexistent.
Same story with Palm OS, which once held the second position in the market rankings with a share of 22% but is - back as of 2009- already nowhere to be seen anymore.
Android, on the other hand, a Linux-kernel based OS developed around 2003 by Andy Rubin, taken over by Google and unveiled in 2007 for large-scale mobile use, grabbed in less than a decade close to 70% of the global marketshare with Apple and its own OS Apple iOS retaining 18%.

With the emergence of the Pocket PC smartphone-edition in 2002, OSs from Microsoft, the 800 pound-Gorilla among the operation systems, gained some momentum and initially even ate substantially into Palm's share.
While Microsofts early Mobile OS 2002-6.5 was not too bad - but still too complicated, unreliable and crash-prone -all subsequent sucessors even after the takeover of Nokia never managed to increase their modest market-share beyond around 3 %.

Microsofts original undisputed advantange - the easy syncronisation between Handheld and PC - had long been taken over by Apple iOS and Android and does not represent any real Microsoft-unique USP anymore.

And while transfer between PC and Handheld still matters, it's the Internet which has taken over as gateway for data-exchange. Today "click-and-transfer" has become the standard for all OS - but for malware unfortunately as well!

... with PDA & SMARTPHONE and more...

In short - we are talking about a market with over 3,5 billion internet-enabled units
and more than half a trillion USD in direct and indirect revenues!