"Frankly, it strikes me a philosophical divide akin to the one
that exists between the Apache camp, which favors permissive
licensing terms, and the FSF, which advocates reciprocal-style
alternatives. Not solely in the depth of the divide, in fact, but
also in its persistence.
"The poster child for the debate, typically, is MySQL. MySQL,
you'll recall, is a project which is an open source project (we can
have that debate later) developed almost entirely by a single
vendor. Unlike projects such as Linux, which are developed
collaboratively by multiple entities, MySQL alone bears the burden
of development, in return for which they retain rights that
developers of Linux do not. Among them, the ability to relicense
the code under more liberal terms than the standard GPL--the
foundation of the so-called 'dual license' model..."