Polish Security Researchers at the Warsaw University of Technology have come up with an innovative method to exchange hidden messages utilizing the GoogleSuggest service.

You can find more information about it here:

Spies can send messages hidden in a Google search - tech - 17 June 2011 - New Scientist

The most frequently used English Words (source: wordfrequency.info) are appended to the end of google search suggestions before they are sent to the google client.

Steganogram Senders and Receivers are the intermediate network nodes between the Google Suggest Client and Server.

Here's a short video demonstration of this method as well:

StegSuggest (Steganography in Google Suggest) - YouTube

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