[jccooper]

An explicit renewal regime with some reasonable fee would allow most works to pass into the public domain, and avoid objections from owners of still-valuable properties. (I like the concept of renewal fees escalating each period, a kind of dutch auction against the public domain, but I'd accept even a fairly trivial flat fee as the price of avoiding ever-longer universal copyright.)

[toast0]

Explicit renewal is also nice, because there's more likely to be updated contact information, which makes licensing more likely.