If you have a question that isn't answered here, please submit it to Dave.
There will be a FAQ here for ACL questions as they come up, please check this page from time to time...however, let's answer what will likely be a common FAQ right away....
Let's give the answer in a nutshell: Never!
OK, not quite "Never"...if you try to create a piece of software that competes with the ACL-licensed software, or you want to "repackage" the software with your own modifications, there are a few special caveats you must abide by. However, even under these conditions, you might be able to deliver/sell your software outside of the ACL terms. The bottom line is that the ACL is a mechanism established by the copyright holder to allow you to freely incorporate his/her software into your without fear of "contamination", reprisal, or legal tangles
The honest answer is that they both generally are the same thing, but the ACL is much more liberal in its licensing terms. Also, the ACL doesn't have any kind of heavy, dogmatic "Manifesto" to go along with it. Using software should be simple, and you shouldn't have to listen to a sermon to use it guilt-free :-)