When Google began displaying contextual ads inside Gmail based on the content of each e-mail, the move generated lots of attention.

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Then, according to the newspaper, it received an e-mail describing how the writer planned to move on from killing animals to people.

CNN: Canadian dismemberment suspect arrested in Germany

An address on an e-mail, for example, can appear over the text as a map with a move of the computer mouse.

FORBES: The Business Mash