When you sign up for your Promoter account, you're automatically subscribed to receive weekly digests for each of your campaigns. To modify this setting, you'll visit your User Profile in the upper right of the app and uncheck 'Weekly Digest' in the Notifications section.
The weekly digests will help you be up-to-date on how your campaign is currently doing. You can view the rolling 30 and 90 day NPS score with a few other stats. The Survey Summary provides further info about your 90-day NPS.