[bruce511]

Sure, that's in the copyright notice, maybe in the docs no-one reads.

But from a marketing and sales point of view, it's nowhere.

For example, I can start marketing and selling a new image editor (blimp), and on my web page, in videos, Facebook yo face, I need make no mention that it's based on Gimp.

And that is -explicitly- allowed by Open Source licenses. Which is part of the Ooen Source deal - others can build on what you made, take credit for it, profit from it. That is not a bug, it's a feature which was explicitly allowed for.

[thayne]

> I need make no mention that it's based on Gimp.

You would however, need to make the source code available under the GPL license, since GIMP is licensed with GPL.

[bruce511]

Of course. But my point is that that a) does not matter to 99% of the people who bought Blimb and b) its not a factor in the marketing and sales part.

[joshka]

> That is not a bug, it's a feature which was explicitly allowed for.

I agree entirely :) It's why I prefer to use the MIT / Apache Dual license (and generally to avoid the GPL in certain contexts).

Apache's condition is more explicit and nicer from the attribution perspective

       (d) If the Work includes a "NOTICE" text file as part of its
          distribution, then any Derivative Works that You distribute must
          include a readable copy of the attribution notices contained
          within such NOTICE file, excluding those notices that do not
          pertain to any part of the Derivative Works, in at least one
          of the following places: within a NOTICE text file distributed
          as part of the Derivative Works; within the Source form or
          documentation, if provided along with the Derivative Works; or,
          within a display generated by the Derivative Works, if and
          wherever such third-party notices normally appear. The contents
          of the NOTICE file are for informational purposes only and
          do not modify the License. You may add Your own attribution
          notices within Derivative Works that You distribute, alongside
          or as an addendum to the NOTICE text from the Work, provided
          that such additional attribution notices cannot be construed
          as modifying the License.

I've actively said to people as a result of looking at my own Apache/MIT licensed software (as well as others) to go fork themselves. You don't need my permission to do so as by choosing that license I already gave you the permission.

[ranger_danger]

Any time I bring this up to people it's immediately shot down with "but it goes against the spirit of the license, and/or the developer's wishes, or is somehow otherwise unethical."

And at that point you basically can't disagree without looking like a ghoul.