> In my understanding, the following
> states that any software that uses PyMeld needs to be make its source
> code available at the cost of distribution plus a nominal fee.  That
> doesn't seem to apply to many kinds of money-making use.
>
> #  * Redistributions in any form must be accompanied by information on
> #  how to obtain complete source code for the software and any
> #  accompanying software that uses the software. The source code must
> #  either be included in the distribution or be available for no more
> #  than the cost of distribution plus a nominal fee, and must be
> #  freely redistributable under reasonable conditions.

There's no talk of *use* here - the key term is "redistributions."

It is true that you cannot use PyMeld within a closed-source product.  The
same is true of any software licensed under the GPL; think of MySQL or Qt,
for example.  Commercial licenses are available for those (free) products
as well Whether that restriction makes the software "unfree" is fodder for
decades of debate.  Free licenses as defined by OSI or Debian, however, are
allowed to have this sort of language.

> The FSF would surely object to
> the "advertisement clause" that was also there in earlier versions of
> the BSD license ("Redistributions of source code must retain the above
> copyright notice..." and "Redistributions in binary form must
> reproduce the above copyright notice,").

Preservation of a copyright notice is not an advertising clause.  The GPL,
too, requires such things:

        If the modified program normally reads commands interactively when
        run, you must cause it, when started running for such interactive
        use in the most ordinary way, to print or display an announcement
        including an appropriate copyright notice and a notice that there
        is no warranty (or else, saying that you provide a warranty) and
        that users may redistribute the program under these conditions, and
        telling the user how to view a copy of this License.

Advertising clauses require giving credit to an original copyright holder
just about anywhere the software is mentioned.

jon

Jonathan Corbet
Executive editor, LWN.net
corbet@lwn.net