Typically, MTU counts increase when you have an increase in users or visitors on instrumented parts of your application. Occasionally, a big press release or marketing campaign can lead to an influx of visitors.
The other potential cause of big increases is that you added tracking to new parts of your site or workflow, maybe it’s a marketing site that didn’t have tracking before, or ramp-up in the number of interactions you have with your users outside your app (emails, help desk, push notifications, etc). Since you are now tracking users you weren’t tracking before, your MTU count will go up. If you’re already tracking those users elsewhere with Segment, we won’t double-count them.
If you suspect there is an implementation error causing your MTU number to rise please contact us immediately and we are happy to help you resolve the issue.