Successful online-learning models so far have learned a shared objective across millions of users rather than learning different things for each user.

“all of the successfully shipped online learning models have had to learn the exact same thing across millions of users. For example,”

“the cursor tab model online learns by predicting the same exact objective for over 400 million requests a day,”

“the objective here being which edits actually got accepted.”

“accepted by the user.”

“At least so far, we haven't seen models online learn different kinds of things for different users.”