A while back Amazon made changes on their Kindle Highlights back-end.
Sadly, Kindle Daily Review was not incorporated into Amazon's migration to Kindle notes.
The Kindle Daily Review was based on the Ebbinghaus forgetting (retention) curve.
The forgetting curve hypothesizes the decline of memory retention in time. This curve shows how information is lost over time when there is no attempt to retain it. A related concept is the strength of memory that refers to the durability that memory traces in the brain. The stronger the memory, the longer period of time that a person is able to recall it. A typical graph of the forgetting curve purports to show that humans tend to halve their memory of newly learned knowledge in a matter of days or weeks unless they consciously review the learned material.
The forgetting curve supports one of the seven kinds of memory failures: transience, which is the process of forgetting that occurs with the passage of time.
san's the Daily Review.