The passage discusses the process behind creating and personalizing notifications in Duolingo to encourage users to engage with their language-learning experience.

Here are some key points from the text:

1. Only high-quality templates get permanently added to the notification pool.

2. New notifications undergo testing on a small group of learners before being implemented for all users as part of an operating principle that 'Test everything.'

3. These tests aim to keep things fresh and engaging by periodically updating existing notifications.

Regarding personalization in notifications:

1. Duolingo uses pre-written messages but adapts them based on various factors, including:

- The language being studied

- The user's current streak

The passage then shifts focus towards the AI system behind these personalized reminders:

2. In 2020, Duoligon's Machine Learning Engineers developed an AI algorithm to determine which reminder message should be sent to each learner daily.

3. This novel approach was presented at the Knowledge Discovery and Data Mining (KDD) Conference in a paper and short presentation.

The text concludes by highlighting some interesting facts about these notifications:

4. The persistence of Duolingo's reminders has become so well-known that it has even inspired internet memes, often humorously referred to as 'Duo' or just 'the persistent notification.'

5. Daily practice is crucial for language learning; therefore, Duoligo uses personalized daily reminders through its AI system to encourage users to stay on track with their studies.

Overall, the passage provides insight into how Duolingo's AI-powered notifications are designed and delivered to individual learners based on various factors such as their study preferences, progress, and engagement patterns.

In a nutshell yk animation