On 13-Jul-09, at 10:37 AM, Joop Sint Jago wrote:

Regardless of legal status. How can one "grab" Drupal for free (with all related benefits) and then refuse to contribute back?

http://www.fsf.org/licensing/licenses/gpl-faq.html I'd suggest reading up about the AGPL license as well as it will help to answer your question: http://www.fsf.org/licensing/licenses/agpl-3.0.html --Andrew