TeamViewer is a form of Remote Desktop, but as for working with the customer supporter.
Its characteristics are likely to use to control the customer whether the customer computer is located behind a NAT or firewall. In addition, the Supporter can put your company logo on the client side software.
Imagine if you are a software vendor or SX printer. You can support global customers on how to install, use and troubleshooting that your employees do not need to go anywhere. great.
Is a program with Open source GPL lisense but sold as a shareware program for use, will be through the TeamViewer server. Is shareware should be free (free of charge) with limited features.