You can disable site activity feeds so that updates from specific sites aren't included
   in your email notifications or the My Activities dashlet on your dashboard.
 
  - Open the user menu on the toolbar and click My Profile.
 - Select the Sites page.
 - 
    Click Disable Activity Feeds to disable updates for a site.
    
You can do this for as many sites as you want, and you can click Enable Activity Feeds to switch feeds back on again.
Note: The My Documents dashlet will still display details of content from the sites you've disabled feeds for.