Sitecore implemented a significant configuration change affecting xDB tracking behavior. The system now restricts tracking to identified users by default—those who have logged in, clicked ExM links, or had Sitecore.Analytics.Tracker.Current.Session.Identify(identifier) applied to their session.

This shift prioritizes performance and reduces index congestion, as every session previously populated xDB. The official rationale states: To improve performance and optimize indexing, we changed the default value of ContentSearch.Analytics.IndexAnonymousContacts setting from true to false.

The Problem

Sites without e-commerce or subscriber bases may find this problematic. Organizations relying on anonymous behavioral signals—IP addresses, company information, location data—for personalization lose critical tracking capabilities.

Configuration Solution

The relevant file is Sitecore.ContentSearch.Analytics.config. Locate the setting:

<setting name="ContentSearch.Analytics.IndexAnonymousContacts" value="false"/>

Changing the value to "true" restores full user tracking, including anonymous visitors.

I recommend implementing this patch for all instances requiring anonymous user tracking functionality.