Question ...

[Arnoud Engelfriet]

J Greene wrote:
>  I don't know if I am in the right place for this but I have a general
> question about the GPL.  I am evaluating a GPLd program that claims that
> when used in a commerical entity requires the purchase of a licence.  

That's a common mistake. They probably meant to say "if you want
to use this in combination with proprietary, closed-source software,
then you will have to purchase a license".

You're free to use GPL software for any purpose, including
any commercial purpose. You just have to comply with the
GPL's requirements. One of them is that if you distribute
a derivative work of the GPL software, you have to make the
source for that derivative available under the GPL as well.

There are companies that do not want to share derivatives
under the GPL's terms and conditions. For these companies
the purchase of a different license is a preferred option.

This kind of licensing structure is called "dual licensing":
http://www.oss-watch.ac.uk/resources/duallicence.xml
http://linux.sys-con.com/read/49061.htm 

Arnoud

-- 
Arnoud Engelfriet, Dutch & European patent attorney - Speaking only for myself
Patents, copyright and IPR explained for techies: http://www.iusmentis.com/