There are situations where Apple can improve the user experience by getting insight from what many of our users are doing, for example: What new words are trending and might make the most relevant suggestions? What websites have problems that could affect battery life? Which emoji are chosen most often? The challenge is that the data which could drive the answers to those questions—such as what the users type on their keyboards—is personal.
Apple has adopted and further developed a technique known in the academic world as local differential privacy to do something really exciting: gain insight into what many Apple users are doing, while helping to preserve the privacy of individual users. It is a technique that enables Apple to learn about the user community without learning about individuals in the community. Differential privacy transforms the information shared with Apple before it ever leaves the user’s device such that Apple can never reproduce the true data.
This is a really interesting paper from Apple describing how they gather data from users but anonymize that data. Of course, all you’re going to read from most media outlets is “Here are the most popular emoji!” And people wonder why Apple “dislikes” the media.