2. Monopoly Mania
The downside of dominating an industry is that you're an immediate target for antitrust allegations. Microsoft experienced this during the late 90s and early 2000s, with accusations of unfair business practices against competitors such as IBM, Real Networks, Gateway, Netscape, and Apple.
(See: "Microsoft Declared a Monopoly")
Google's antitrust headaches have just started, with European legislators looking into how it treats its search and online ad competitors. The company is also meeting fierce opposition from the online travel industry following its announcement of its intention to buy ITA Software, a flight-data aggregation company.
3. It's the Platform, Stupid
The core strategy for both Microsoft and Google has been to create a platform that keeps the user in each company's ecosystem. Microsoft led the way in the 1990s by distributing the most popular desktop operating system ever and offering tools that played nice with Windows, such as Microsoft Office, Internet Explorer, and early online "cloud-based" services like Hotmail.
In addition, it's making a big push to popularize Web apps through its Chrome Web store and the forthcoming Web-focused Google Chrome OS. Google also recently stepped up its game in encouraging third-party development for its Android mobile operating system, with new features such as a Web-based store for browsing apps and an in-app payment system.
Microsoft faced little challenge to its ecosystem in the 1990s, while Google faces formidable challenges from Apple's iOS platform for mobile devices and Facebook's continuing push to become the dominant platform on the Web.
4. Apple Rivalry
Microsoft is the new IBM, Google is the new Microsoft, and Apple is the new...Apple?
After the release of Windows 95, Microsoft ate away at Apple's business, driving the Macintosh maker into a niche market. Microsoft's strategy of distributing Windows on as many platforms as possible was a huge success, a contrast to Apple's distributing of the Mac OS only on its own computers.
Fast-forward to 2011, and Google is trying to beat Apple's iPhone and iPad using a similar strategy: Although you will find iOS only on the iPhone and iPad, Android is on pretty much everything else, including devices from HTC, Motorola, Samsung, and Sony. Android's smartphone market share is steadily overtaking that of iOS.
The most recent numbers from Nielsen say that new smartphone users are choosing Android devices over iPhones by nearly 15 percentage points, while the iPhone platform maintains an overall lead of about 3 percent. It hasn't happened yet, but Android is threatening to push iOS devices into a niche market much as Microsoft shoved aside Apple's Macintosh.
Next: From Rebel to Lumbering Giant