4. Google
It's not just through Android that Google is positioning itself to be the dominant force in technology. While it continues to take on Microsoft in the PC market with its ever-expanding range of cloud services, and is set to launch its highly anticipated browser-based operating system Chrome in 2010, it's in the mobile space that Google is really looking to rule.
Android will probably become one of the top three mobile operating systems in the next year, but let's not forget that the majority of Google's revenue comes from good, old advertising. As the service of choice for people looking for stuff on the web, Google receives money from any company looking to advertise itself online and it wants to replicate that on mobile devices.
Mobile commerce is set to boom next year and people are going to need more help than ever finding stuff via their mobile devices due to the relatively restricted user interface. If Google is successful in acquiring AdMob, it will dominate not only search advertising online, but display too.
While competition will only intensify in the mobile space, Google's biggest threat could come from regulatory authorities, as it starts to get a bit big for comfort. Poking its nose into things like book publishing and launching its own handset will serve to make it ever more conspicuous in their eye and it could end up emulating Microsoft more than it ever intended.