In the context of products and services, adoption is the act of beginning to use something new. Considering new features and new users, there are four types of user adoption:

  1. Internal adoption: When existing users begin using new features. For example, the percentage of existing Instagram users who adopt a new story feature within 1, 7, or 30 days of its introduction.
  2. External adoption: When new users begin using existing features. For example, the mean number of days new Instagram users create their first story from when they opened their account.
  3. Adoption flags: When new users adopt new features. A green flag is raised if they’re successful, and no red flags are raised when they’re not.
  4. Routine adoption: Happens when existing users adopt existing features.

User adoption is an unbiased behavioral measurement and is therefore trustworthy, valid, and reliable

Number of New users / Total number of users) / Period of time