What is the Email Digest feature?
The Email Digest feature bundles activity notifications of Deals, Leads, and MDFs into a single email.
How often are digest emails sent?
Digest emails are sent approximately one hour after the first notification event, so Users will receive no more than one digest email per hour.
Is this feature available to all Users?
Yes, the email digest functionality is available to all Users; however, only notifications sent to email addresses associated with actual Users get consolidated into the digest format. Emails sent to distribution lists or recipients that are not associated with actual Users such as "partners@yourdomain.com" or "channelmarketing@yourcompanyname.com" can't be consolidated to the digest format.
How do you enable and disable the feature?
Global Default Setting (Applies to ALL Users)
As a System Admin, you can enable the Digest feature for all portal Users by going to Settings > Email > Email Settings. You'll then scroll down to the Digest Email Settings section below to make your changes.
Personal Email Setting
Users can enable and disable Digest Email Notifications in their individual User Profile settings by clicking on the profile icon in the top right corner of the page and selecting “Email Settings." 
Scroll down the page to the "Email Notifications" to enable/disable the Email Digest feature.
Is the Email Digest customizable?
The email template layout cannot be customized. However, Admins can modify the subject line and insert a message at the top of the Digest email template by navigating to Settings > Email > Email Settings, and then scrolling down to the "Digest Email Settings" section. 