Disable Chatter Digest Emails
Personalize Chatter Email settings Follow below steps to modify Email settings for the Chatter. 1. Login to SFDC and navigate to Tab ‘Chatter’ 2. Click on ‘Groups’ link. 3. From the list choose the group to stop/modify notification for. 4. On left hand side click on ‘email me’ link. 5. Now you can choose one of below. Also you can fine tune more settings by clicking on ‘Email settings’ link. Hope this helps.