Generally when a trademark is registered at the Patent and Trademark Office, the identification of goods and services offered under the mark may not be changed. The application for registration of the mark is published, and the world is on notice of the intent to register the mark with the specifically identified goods and services.
However, in the world of rapidly changing technologies and the means of delivering goods and services, static descriptions may not be realistic or helpful. Accordingly, the Patent and Trademark Office has announce a pilot program to allow amendments to the identification of goods and services that are otherwise beyond the scope of the current identification.
More information is available at http://www.uspto.gov/sites/default/files/documents/Technology_Evolution_Pilot_Program.docx.