Development of Creative Commons licenses

[Josh Rosenblum <joshrose AT rosenblums.org>]

General question about constraining the effectivity date of CC licenses.

Suppose I have content, whether music, text, or metadata, which I'd like 
to release under a CC license, but with the following caveat:

To help pay for the production of this content, I plan first to release 
it in a limited fashion, charging those who place a high value on 
freshness of the content.  Once the restricted-release period is over, 
the content would be released under a standard CC license.

This situation is common in time-sensitive, stream-like media such as 
stock quotes or financial news.  However, segmenting markets according 
to time-sensitivity is also an established way to support the production 
of static content.  I think combining this with CC may provide proper 
economic incentives in some situations while explicitly growing the 
_future_ commons.

As I understand, the only way to shoehorn this into the CC view of the 
world would be to release content under some custom license for the 
initial embargo period, then re-license it under one of the CC licenses 
at a future date.  This seems kludgey, and perhaps I'm missing something.

Should CC licenses define effectivity dates, it might address this 
problem.  In addition, if the licenses internalized this 
time-sensitivity, then the content's metadata remains within the purview 
of the CC RDF/metadata tools from its moment of release.

I'm curious if the CC community has considered this situation and what 
suggestions y'all might make to accommodate it.

Thanks,

-Josh Rosenblum