Question

Why did my Segment MTU count increase unexpectedly?

Product

Twilio Segment

Environment

Segment Console

Answer

MTU increases usually happen when Segment tracks more unique users than before. This can be caused by changes in traffic, new tracking implementations, imported data sources, or changes in how user identities are managed.

Common reasons for an increase in MTUs include:

• Changes in traffic
  • An increase in visitors or users interacting with areas of your website or application that use Segment tracking can increase your MTU count.
  • Large marketing campaigns, press releases, promotions, or increased usage of your application can result in more tracked users.
  • Adding Segment tracking to new pages, features, or parts of your application that were not previously tracked can also increase MTUs.
• Changes to imported sources
  • Importing additional user interactions from Cloud Sources, such as emails, help desks, or push notifications, can increase MTUs.
  • If Segment cannot associate these users with existing users (for example, if a userId is not provided), they may be counted as new MTUs.
  • If users are already being tracked by Segment and can be resolved with an existing identity, they are not counted again.
• Multiple anonymousId values being generated for the same user
  • If the same person generates multiple anonymousId values and those identities are not linked to the same userId, Segment may count them as separate MTUs.
  • Common reasons a new anonymousId may be generated include:
    • The user visits from a different browser or device. Each browser or device maintains its own anonymousId.
    • The user browses in Incognito/private mode. A new anonymousId may be generated for each private browsing session.
    • The user clears their browser cookies. This removes Segment tracking information, including stored anonymousIds and user identity information. When the user returns, new tracking information is generated.
    • analytics.reset() is called. This clears the user's identity information and generates a new anonymousId.
    • An existing anonymousId is overwritten using methods such as analytics.user().anonymousId(xxx). Overwriting identity information can cause a user to be counted separately.
• Cross-domain tracking
  • If your tracked pages are hosted on different domains (for example, mydomain.com and mydomain.net), each domain stores its own cookies. As a result, a user may receive a different anonymousId on each domain.
  • Subdomains (for example, mydomain.com and app.mydomain.com) can share identity data and may count as a single identity.
• Tracking within an iframe
  • If a tracked page loads inside an iframe, the page inside the iframe may generate its own anonymousId instead of using the parent page's identity information.
• Browser privacy settings and tracking restrictions
  • Privacy features, cookie restrictions, consent tools, and tracking prevention settings can prevent Segment from storing identity information.
  • When identity information cannot persist between visits, returning users may generate new anonymousId values, which can contribute to additional MTUs.

To help reduce unexpected MTU increases:

• Identify users with a consistent userId whenever possible.
• Avoid overwriting existing identity values unless necessary.
• Review changes to tracking implementations, new sources, and calls to analytics.reset().
• Ensure imported sources are correctly resolving users to existing identities.