If the Facebook site/app goes the way of AOL/MySpace, which it won't for a long time, they have already prepared for that.
Temporary monopolies can be sometimes good like AT&T building telco/software with Bell Labs and C++ etc, Microsoft with the desktop and getting people online, early ISPs to get broadband started, but they usually end up abusing that position eventually.
Some companies get greedy when they get the market leader monopoly power and it can lead to less innovation if they focus on limiting competition rather than beating the open market.
Microsoft started to abuse their position eventhough they had won. Then Microsoft got slowed down both from the anti-trust/monopoly DOJ/EU strainer and the subsequent miss of iPhone/Android mobile market.
Microsoft got humbled and returned to innovation and is a better company for it today, but has lost power they once held. That speedbump allowed Google (Android/Cloud/Search), Apple (iOS), Amazon (Cloud), and more to rise. Ultimately slowing down Microsoft even a bit re-opened innovation and bettered everyone's quality of life when they had started stiff-arming and blocking competition rather than innovating.
There is a lesson to companies that get the market monopoly or top positioning, stay competitive and don't slow down innovation by attacking others, continue to research and develop and innovate. Resorting to limiting others to get ahead in competition makes the companies forget why they are the market leader, win in the open market and innovate to stay the leader.
Companies on monopoly/market leader watch: Google, Apple, Amazon, Facebook and others in tech. Some that have already gone beyond acceptable limitations of stifling innovation include Comcast, Verizon and AT&T and are in need of breaking up again as they turned to favored markets rather than neutral. These companies are not winning with better products but winning with bribes, lobbying and limiting innovation only.
As long as companies stay focused on innovations and winning in the fair competitive market, not with limiting others beyond open fair market competition, they will stay ahead and not forget why they are the leader. Market leaders should innovate instead of being the bully.
What? Android and Vista are on two different spaces. You are comparing mobileOS to a desktop OS?
Android didn't compete with microsoft. It competed with apple.
Yes, there was Palm and PSION before that, both of which I used heavily, but Windows CE had a massive marketplace for applications and seemed to coincide with WiFi and the web really taking off. This feels very odd to say, but mobile Internet Explorer was impressive - and even supported flash!