Now that polarization is almost complete in the industry.
Microsoft is still the leader in the desktop space, with Windows Operating System. Apple is second with Mac OS X, Linux is probably at Number 3.
Google is inching closer to achieving monopoly in the web space. It probably just needs to acquire Yahoo, AOL and FaceBook (and shut down Orkut, if merging proves to be difficult). MSN and Lycos will remain to cater to rest of the market till Google acquires more and more of it.
Oracle has already acquired Siebel, Peoplesoft & JDEdwards, Agile, BEA Systems and so on.