How high can Google shares fly? It seems entirely possible they could break through $600 by year-end based on the growing enthusiasm among analysts. Bear Stearns has raised its 12-month target price by 53% to $550 - citing Google's "ecosystem". Meanwhile, Piper Jaffrey is looking at $600, which SiliconBeat calls "outrageous". So what's behind this excitement? On one hand, there is no doubt Google is a business powerhouse as the online advertising market rumbles forward. But I think another critical element in the investment mix is Google's strategic fuzziness. By this, I mean there are dozens of directions Google could go but few of them have become apparent yet. For example, does the company drive hard into video by launching a downloading service or acquiring Tivo? Does Google become a major content player by raising its stake in AOL? Will Google launch a $200 PC? And what about the Google Cube - the home networking device that Robert Cringely talked about in a recent column? (CNet has a story about the mystery of the Google Cube while John Battelle dismisses the idea.) I think it's the mystery of the unknown that, in part, is capturing the imagination of investors. Instead of shying away from the unknown, investors are being drawn to Google because - like a good mystery story - you never know what's going to happen next. That's a critical part of the allure.

In other Google news (and there's never seems to be a lack of it), Search Engine Watch reports that Google has received a patent to accelerate traffic on CDMA wireless networks. (hat tip to Om Malik). Google shares were up nearly $10 by mid-morning to $444, which gives the company a market capitalization of $131-billion. The Street.com's Kevin Kelleher has a good story looking at the why investors should be bullish and bearish on Google, while Nicholas Carr has some thoughts on the monetization of eyeballs.