The disclosure provides technology for adaptively creating and adjusting reminder notifications for a first user based on activity of a second user. An example method includes identifying an electronic message transmitted between a first user device and a second user device; accessing data associated with a user of the second device, wherein the data comprises activity state data for the user; determining a notification time for the first device based on the data associated with the user of the second device; and updating a reminder related to the electronic message based on the notification time.