If Google is strong enough to say no to Microsoft, then why does it need to go public? The best argument I've seen is that Google is almost compelled to because the number of employees it has will force it to make quarterly public filings....this as the reason Microsoft went public, and indeed, it was.
from here: ht*p://searchenginewatch.com/searchday/article.php/3104441
Microsoft did not need to go public. It certainly did not need the money. By 1985, largely on the strength of its MS-DOS operating system, it had cash of $38 million and was earning more than $27 million per year. Bill Gates was reluctant to have Microsoft go public -- as reported in Fortune, he worried that it would be a "pain":
"The whole process looked like a pain," [Gates] recalls, "and an ongoing pain once you're public. People get confused because the stock price doesn't reflect your financial performance. And to have a stock trader call up the chief executive and ask him questions is uneconomic -- the ball bearings shouldn't be asking the driver about the grease."
However, Microsoft had granted so many stock options to so many employees that it feared that by 1987 it would have 500 stockholders and be forced to register under Section 12 of the Exchange Act. Rather than let that happen to it, Microsoft decided to call its own shots and go public when and how it wanted.