Everyone send emails now: political parties, your book club, freelance journalists the social networks you're signed up to, your parents, that online store that you only bought one item from a decade ago, and many, many more.
What do a lot of those email senders have in common? They want to know whether the messages they send you are being opened, and there are a variety of tools available to help them do just that—tools that aren't all that hard to use.
A tracking pixel, embedded somewhere in the email, is how most people monitor whether an email gets opened. Once the tiny, hidden single-pixel image is loaded, it reports back to base. Their use across emails is now up to "endemic" levels, according to some experts.
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