I was also taken by surprise when I saw "ArsDigita Public License". I read the license and can say straight out front that it is NOT compatible with the GPL because of the advertising clause:
"Acknowledgment. All advertising or promotional materials, download pages, documentation, and/or physical media mentioning features or use of this software, and any redistributions in whatever form, must display the following acknowledgment in a reasonably prominent location: "This product includes software developed by ArsDigita Corporation for use in the ArsDigita Community System (ACS) (http://www.arsdigita.com/acs/)."
This is the one that strikes me up most, but there are probably other things. In the license it also says that "Except as required by the Acknowledgment section below, products derived from this software may not be called "ArsDigita Community System" or "ACS" and such names may not appear in the name of any such derived product without prior written permission of ArsDigita. To request written permission, contact mailto:info@arsdigita.com. "
I agree with Ben. OpenACS developers, please do not get close to ACS 4.6 until we give further recommendations. This is to avoid any problems to OpenACS as a project.
