To be sure, Google's appeal is undeniable. Its shares have risen more than 350% since going public last year. And Wall Street analysts are predicting that the company will have better revenue growth in the fourth quarter than other tech giants, including its rivals Yahoo! ( YHOO) and Microsoft ( MSFT). Because of its embrace by investors, Google, which was founded seven years ago, now has a market valuation of $112.7 billion, surpassing the $109 billion value of tech bellwether Cisco Systems ( CSCO) and the $58.7 billion market value of Motorola ( MOT). Even more remarkable: Google's market cap is creeping close to those of 88-year-old IBM and 168-year-old Procter & Gamble ( PG). Google has beaten Wall Street estimates for three straight quarters. Analysts' profit estimates for the fourth quarter range from $1.48 to $1.91 with sales seen between $1.15 billion and $1.91 billion. Yearly forecasts range between $5.39 and $6.18 with sales expected at $4.07 billion to $6.13 billion, according to Thomson Financial. The wide range of estimates, coupled with Google's short operating history, make it difficult for investors to figure out if the company's shares are fairly priced. "It's an intriguing company, but I don't know how to value this kind of company," said Hodges of First Dallas Securities. "Its obviously selling on promise, and their history is so short that you really can't make too many assumptions about." Google's rise also brings back memories for George Schwartz, president of Bloomfield Hills, Mich.-based Schwartz Investment Counsel, of other booming companies that investors pinned their hopes on, only to be disappointed. "There's always been cycles for mania," said Schwartz, adding that it's part of human nature. "People want something for nothing."