ERDDAP has an email/URL subscription system so that you can be notified immediately whenever
a dataset changes (for example, whenever new data is added to a near-real-time dataset).The system can send you an email or contact a URL that you specify.  
See also this 
comparison
with ERDDAP's RSS subscription service.
 
Or, you can request an email with a
    list of your valid and pending subscriptions.
It includes URLs to remove each of your subscriptions.