Activity Index is a composite activity indicator for Twitter, Instagram, and YouTube. It is the equivalent of Facebook Interactivity Index. You will find more info about Activity Index on our blog.
Interactivity Index (or InI, as we call it for short) is a composite activity indicator on a Facebook Page. It helps you to see which content was the most engaging (including different weights of different kinds of activities). A more detailed description of InI can be found on our blog.