Brian X Chen, writing for the New York Times:

It didn’t take much for Florian Seroussi, a technology investor in Manhattan, to become suspicious of his email.

His misgivings were sparked late one night last year when he opened a message from an entrepreneur who was asking him to invest in a start-up. Minutes later, Mr. Seroussi’s cellphone rang with a call from the same start-up executive.

Coincidence? Not to Mr. Seroussi. “What are the odds that at 10:30 at night, a guy suddenly has a vision that I’m reading his email?” he said. “They must know something that I don’t.”

It turned out that the start-up executive had planted a tracking mechanism into his message to Mr. Seroussi, a trend that is increasingly afflicting all of our email. Trackers, which come in many forms including a single invisible pixel inserted into an email or the hyperlinks embedded inside a message, are frequently being used to detect when someone opens a message and even where that person is when the email is opened. By some estimates, trackers are now used in as much as 60 percent of all sent emails.

This is why we can’t have nice things.