Copyleft-next and the kernel

Copyright should be short, and transition to trademark when it expires, if it's still of value. So Disney could protect Mickey with trademarks, and the rest of us get to access all that stuff that's old and worthless after 10 years (I don't know the figure, but the commercial value of most copyrights after that long is about £0.00).

Or just create a "register of extended copyrights" which it is the copyright holder's duty to keep up-to-date. If you don't keep your contact details up-to-date every, say, 5 years so that people can contact you for permission, it falls off the register and can't be put back.

Imho for personal copyrights at least term should be the greater of 25 years, life of author, or 120th birthday of author. That's not really a major change from what it is now. Commercial copyright is a bit more tricky ...

Cheers,
Wol