I had always believed that the extensions provided by the Mozilla team were all open source and did not require a license. So when I received this link for Terms and Conditions for the popular StumbleUpon Toolbar, I was somewhat surprised. According to the email I received, the concept that ALL extensions for Firefox are open source is in error. They do list some proprietary software such as StumbleUpon in their add-on listings.

The terms and conditions state:

This Toolbar License is a legal agreement between you, the end user (“End User” or “you”) and StumbleUpon, Inc., located at 140 2nd Street, 3rd Floor, San Francisco, California (“StumbleUpon”, “us” or “we”), for the license of the StumbleUpon toolbar for the Microsoft Internet Explorer web-browser, which includes computer software and electronic documentation (the “Toolbar”). 

What do you think? Should Mozilla allow licensed software as an add on to Firefox or not?

Comments welcome.

StumbleUpon license agreement is here.