Ever get an email, open it, and decide you'll deal with it later? Of course you have. Would you behave differently if the sender was notified that you had opened his email, but failed to respond?

This theoretical question may be a new reality. Earlier today, Streak – a customer relationship management app that integrates with Gmail – unveiled a free new feature that tracks when someone has read your email, what city they read it in and what kind of device they read it on.

“The basic idea is that when you send an email, you get notified immediately whenever somebody reads it,” says Aleem Mawani, Streak's co-founder. “It also gives you historical context. You can go back to any email you've ever sent and see who read it, when, what time, where were they when they read it, what device they read it on.”

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It's easy for Streak to track emails without the recipient even noticing. If you open a “tracked” email on an iPhone or iPad, Streak will automatically notify the sender that you've opened his or her message. If you open a “tracked” email on a computer, a discreet banner will pop up asking for your permission to display the attached images – but only if you haven't emailed the sender before. If you have emailed before, the sender will be notified automatically when you open the message, no permission necessary.

“When Gmail asks you [for permission], it's actually very subtle,” Mawani says. “It's not a big in your face thing...it wouldn't tip someone off that this email is being tracked.”

Mawani doesn't view this as intrusive, and he doesn't predict a backlash in part because it's already happening. Companies like Groupon track whether or not you open their emails all the time, he says. “It's not that we're doing something incredibly new, but what we are doing is making it a lot easier for an individual to do, and a lot easier for you to see the results.”

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Since using the feature in his own inbox, Mawani says he's become more successful at crafting messages. “If you notice that some of your emails take a long time to respond to – whereas others get a quick response – you can start writing better emails.”

Despite its obvious usefulness, this new iteration of email tracking feels uncomfortably personal. Might people resent the tracker for guilting them into answering emails they would have otherwise left unanswered?

“I don't predict it, but that's mainly because of the way I respond to emails is very short and succinct,” Mawani says, although when pressed, he admits that perhaps not everyone is quite so efficient. “We'll have to see.”

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