Google also features a line-up of cloud applications that make it a virtual one stop shop, and greatly enhances its brand, including Gmail, Google News, Google Docs and Spreadsheets, Google Chrome browser, Google reader, Froogle and the neat Google Earth.

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Web ventures like Google Docs, Google Spreadsheets, Blogger and YouTube might not generate much revenue compared with Google's mammoth search business, but they're not mere side projects.

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Customers can email spreadsheets, PDFs, Word docs and other documents directly to their Kindle Fire, or upload documents from their PC or Mac using Amazon Cloud Drive.

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