This feature is available in Enterprise and Ultimate editions.
Follow these steps to stop watching an asset.
Option 1. On any Asset Details Page
Open the details page of an asset.
Select Stop Watching from the Edit menu.
Option 2. On the My Subscriptions Page
Go to My Home > Subscriptions.
Select Delete from the Edit menu.
You can see the list of assets you are watching on the Sub"watched" assets on the Subscriptions (My Home > Subscriptions) page.
All changes made to core and custom fields, including text fields, drop-down lists, numbers and check boxes trigger watch notifications. Note that you will not receive notifications for changes to items that have multiple relationships (except the Owners field).