Google will adapt its AdWords strategy to work better and more cheaply for mobile ads. It's also working with Yahoo. Reuters

For the first time since its 2004 initial public offering, shares of Google Inc. (NASDAQ:GOOG) closed above $800, valuing the search engine and media company at nearly $266 billion. They closed at $805.85, up $13.96 after touching $806.68 earlier Tuesday.

The performance of the Mountain View, Calif., has been slow, especially since the shares first topped $700 in October 2007, then dipped and only exceeded $700 for the second time last Sept. 7, when they closed at $706.15.

On Sept. 21, shares of rival Apple Inc. (NASDAQ:AAPL), set their record high of $705.05, before starting their fall to as low as $435. They closed at $459.99, down 17 cents.

“For me, it’s all about Android,” said Kevin Landis, an investment manager with Firsthand Funds, which manages several technology mutual funds, explained about Google's performance.

Analysts at Gartner (NYSE:IT), a leading technology market research firm, estimated the Android OS for mobile phones has nearly 70 percent of the global market, compared with about 20 percent for Apple’s iOS. Landis said he expects Google to make a lot of money from Android apps and advertising over time.

Google also reported higher-than-expected fourth-quarter earnings and revenue on Jan. 22, since when the shares have gained more than 14 percent. CEO Larry Page said the company would keep monetizing new assets from mobile search.

Few other companies trade above $800.

Best known is Berkshire Hathaway Inc. (NYSE:BRK/A), the vehicle of tycoon Warren E. Buffett, which closed at $152,498., up $2,357 on Tuesday. Another is Seaboard Corp. (NYSEAMEX:SEB, an agribusiness holding company, whose shares closed at $2,850, up $19.18. Shares of LICT Corp.(PINK:LICT), a communications provider, closed at $2,215, down $75.