According to the new policy, Oath now has the right to: "analyse all communications content (such as Mail and Messenger content including instant messages and SMS messages) and all photos and other content uploaded to your account".
The company says it will use this information: "to detect, among other things, certain words and phrases (we call them 'keywords') within these communications."
According to the policy, this technology will be used to protect users, but also to "match and serve targeted advertising (across devices and both on and off of our Services) and provide relevant advertising based on your device activity, inferred interests and location data".
The technology goes to some lengths: the policy describes how the company will use "image recognition algorithms" that can identify places, public figures, actions and more.
Oath isn't the only company to utilise a technology like this – indeed, Facebook revealed that it uses advanced algorithms to scan photos and links sent within Messenger in order to look for illegal or abusive content.
Until late last year, Google's Gmail used a similar technology to scan the contents of its users' messages. It announced in June, however, that it would be stopping the practice before the end of 2017.
In the wake of Facebook's Cambridge Analytica scandal, data privacy has become a lot more visible to the public.
Oath does provide a privacy tools website, which it claims will allow you to disable interest-based adverts, although it's not clear whether users can actually turn email scanning off altogether.