Development of Creative Commons licenses

["Improbulus" <improbulus+cc-l1 AT gmail.com>]

It seems to me that Attribution Non-commercial Share Alike is the closest to what I'm looking for, but there is one point which is unclear to me, and I'd be very grateful if someone would be so kind as to clear it up please?

 

In relation to derivatives, I'd be happy for people to build on my work. But if they have to release their work on the same terms, surely this just means that anyone who then builds upon that derivative work only needs to credit the creator of that derivative work (and get their permission for commercial use etc), and doesn't have to credit me or get my permission as well?

 

In other words am I right in thinking there's only one "generation" of permission/attribution that's needed for share alike, and you don't have to go back to previous/original authors?

 

If the first derivative work is very heavily based on your work, how do you prevent this generation upon generation dilution of your right to be involved, which could of course get worse if someone else produces another derivative work based largely on the first derivative work, etc?

 

Would the only way be to forbid derivatives altogether?

 

Many thanks in advance

Improbulus.