Google, which began trading at $85 in 2004, has the sixth- highest stock price in the U.S. and has surged 27 percent this year. The shares rose $1.84 to $584.39 at 4 p.m. New York time on the Nasdaq Stock Market and earlier reached $596.81.

The search engine has taken users from Yahoo! Inc. and Microsoft Corp., pushing sales growth to at least 70 percent in each of the past three years. Google plans to lure more Web surfers and advertisers through the YouTube video site, bought last year, and has introduced software to sell mobile ads.

"Google is still dominating," Piper Jaffray & Co. Web analysts including Gene Munster said in an Oct. 1 report.

Munster, in Minneapolis, rates the stock "outperform" and estimates it will reach $660 within a year as Google parlays its lead in search into other areas of online advertising next year.

Remember a couple years back when some analyst floated the idea that Google could eventually be worth $2,000 a share--and was ridiculed from coast to coast? Well, first it's worth noting that Google is now almost a third of the way there. Second, it's worth noting that $2,000 a share would mean a market cap of about $750 billion, which--given a reasonable time horizon--just isn't that far-fetched.

Why? First, from a macro level, in every technology wave, the market leader usually ends up amassing more power, wealth, and market capitalization than the leaders in the prior wave, often by a startling magnitude. The leaders in the last technology wave included Microsoft and Cisco, both of which peaked around $500 billion in market capitalization...