Users can manage their subscriptions within the Subscriptions page located within the Manage Push Reporting Tab of Control Panel.  Once you have clicked on the Subscriptions link this page will display the all of the Subscriptions you have subscribed to.  The columns found on this page include:

From the Subscriptions page you can also subscribe to additional Subscriptions by clicking on the Add Subscription button.   In addition, you can also manage Subscriptions from this page where you are the originator, but have not subscribed to the Subscription.  The Add Subscription dialogue box displays all active Subscriptions that are available to you.  Subscriptions are created in Targeter, but you can subscribe to existing Subscriptions within this dialogue box.  The columns found within the Add Subscription dialogue box include:

Users will not be notified if you add or remove them from a Subscription, so it is important that you communicate to your users why you are adding them or removing them from a Subscription.  Users will be sent an email if a User deletes a Subscription that they've subscribed to.