Internet darling Google’s shares surged past $700 for the first time on Wednesday barely a few weeks after the stock breached the $600 barrier.

Defying commonsense, Google shares closed at $707 Wednesday giving the Internet search company a market capitalization of $220.7 billion.

Consider this – Google’s market capitalization is now higher than that of business stalwarts such as Berkshire Hathaway (run by legendary investor Warren Buffet), Citigroup and Bank of America.

Investor mania for Google shares seem to be driven by news of the so-called Google Phone, the company’s ambitious plans on the social networking side, 46% growth in profitability in Q3 and the search for a safe haven in the aftermath of the sub-prime mortgage carnage on Wall Street affecting most of the financial service providers.

Google shares have risen over eight times since the shares debuted at $84 in August 2004.

All of us know how the Tulipmania and the DotCom Mania ended.

Will the Google Mania end any differently?