This largely depends on whether you are a voracious reader who owns multiple ebook platforms, and who does a lot of highlighting and note-taking.
For those users, Readwise will definitely be a worthwhile investment as it will help the user better retain and absorb information.
Readwise offers a 30 day free trial, after which- There are two pricing plan options: Readwise Lite ($4.49 per month, billed annually) and Readwise ($7.99 per month, billed annually). The main difference between the two is that the standard plan allows you to organize your highlights with tags and notes, export your highlights to Evernote or Notion, and get early access to beta features.
Prospective Readwise users need only sign up for their Readwise account and then sync it with their various reading platforms (Nook, Kindle, iBooks, etc.).
Users will then receive a daily email with several notable highlights from their readings to review.
Readwise is a service that helps you compile all the various highlights and notes that you take on various ebook platforms, and then conveniently sends you an email with a few of your top highlights each day. The point of this service is to promote better retention of one's ebooks and articles.
Readwise was the #2 Product of the Day on Product Hunt on September 6, 2018.