If you send an email to a friend who has a Gmail address, then according to Google’s own admission, “You have No Legitimate Expectation Of Privacy”, as brazenly announced by Google in August 2013.
1. Any payment extorted by intimidation, as by threats of injurious revelations or accusations.
Would you be surprised to find out that Gmail actually modifies the text of personal emails if either the sender and/or the recipient of the email are using Gmail? You can conduct a test of your own to verify. Just send a Youtube link to or from a Gmail server. You will see that it has automatically replaced the Youtube link with a hyper-linked Title of the Youtube Video! Test it out. Send an email with a Youtube link (such as this one: https://www.youtube.com/watch?v=–qp1hzsDCM ) to your Gmail account. It will show up with the Title of the Youtube video as shown on Youtube itself, instead. This clearly shows that all of our emails are scanned.
Gmail might not ultimately fit into the above definition of blackmail, however the payment being extorted doesn’t necessarily have to be a payment in “money”. In today’s world, “information” is a form of currency, which can be traded with a 4th party for real money or other favors, which can be secretly transacted under contract. In such a potential situation the recipient Gmail user would be the 1st party. You, the sender of email to your friend, the 2nd party. Google who processes, analyzes and stores your email content is the 3rd party. The 4th party could either be a government agency, another data-mining corporation, or perhaps a private investigator. Email goes along way today doesn’t it?
Google has stated, in 2013:
“Just as a sender of a letter to a business colleague cannot be surprised that the recipient’s assistant opens the letter, people who use web-based email today cannot be surprised if their emails are processed by the recipient’s [e-mail provider] in the course of delivery. Indeed, ‘a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties.'”