Telemetry is a way to collect install based tracking data from Symantec customers. A ping is generated to Symantec CED server over http and the collected data is sent to that server during install/uninstall/upgrade (not during modify/repair) of our products. This turns out to be an excellent tool to collect the data and understand the customer base using that product. This feature will be available since SPSS 6.0 onwards.
Note Symantec recommends to keep telemetry enabled.
For more information on how Telemetry functionality works and other details, refer attached Telemetry FAQ document.