Photo Upload uses your authentication details for the sole purpose of connecting to your chosen upload service (e.g. Picasa Web) and to allow you to maintain your photos and albums on that service from within Lightroom.
Personal details or other information that you enter using Photo Upload are not transferred to any other system. User information is not passed to any third parties or to the software producer.
Photo Upload periodically connects back to the producer’s Website to check which is the latest version of the plug-in. The plug-in does not pass any information back to the producer’s Website.