"Copyleft" is just geek wordplay on the word "copyright," and in my lexicon serves as an umbrella term covering many kinds of agreement, all sharing in common the goal of making it easier to distribute a work without violating anyone's integrity -- because the authors/innovators intended such unrestricted distribution at the outset.
In the education sector, I'm hoping we'll collaborate on building up an archive of digital works that's consciously designed to encourage future students to edit/recombine, as well as value add. For example, I'll go into the archive and find a clip that well illustrates some mathematical principle I want to explain. But how I connect it to other clips, including to new material, will represent value added. I'll contribute my two cents (figurative talk) back to the archive, and so on.
To produce such educational clips for the public sector is not to surrender your right to hold stuff back for a more select crew. A company might contribute several hours of cool video to the archive, while making it clear "there's more where that came from" but to access the larger corporate stash, you have to do some work for the corporation or university. In this sense, copyleft clips serve in part as teasers, in part as recruiting propaganda, and in part as advertisements i.e. they reflect well on the internal culture that produced them.
Also, to produce clips for the public sector is not to squander all the inhouse advantages you've built up allowing you to make such clips in the first place. The concept of open source software sometimes suffers from this same misapprehension: if it's free, it couldn't have been that hard to create.
But the truth of the matter is it still takes plenty of talent, tenaciousness, commitment, to write the stuff, even if the end results go into some public archive, some shared digital library. And whereas others may definitely learn from your examples, it's not like eyeballing sophisticated code is to immediately unlock all the secrets to writing it. Recognizing brilliance is one thing, while showing it off is quite another.
Some coders contribute to the Linux kernel. Anyone is free to read kernel code. Having global access to this code helps, but the world is still not swamped with kernel programmers.
In other words, I think some people mistakenly suppose that contributing artful works to the commons will somehow deprive them of their elite status as persons capable of sourcing said artful works. On the contrary, artists stand to gain by increasing their audience, developing a following, a reputation. Then, if they want to exchange some of their art for goods and services, versus making it freely available to other studios for editing & recombining, they'll have a stronger currency with which to negotiate.
Of course having one's public contributions boost one's reputation depends on preserving attribution, listing credits. The growing library I'm forecasting strongly encourages this practice. Users, players, other artists, should acknowledge their sources, following the age-old practices of good scholarship.
To piggy-back without giving credit is to freeload. To some extent, that's perfectly OK: every human is born helpless and naked, and needs nurturing, free access to information, without a lot of concurrent demands -- just growing and developing is a full time job. But at some point most develop a natural desire to credit community members, both contemporary and ancestral, for their contributions, and to be appreciated in turn. This is the normal economy of mutual advantaging that we've had going, in one form or another, since the dawn of history and before.
As a Fuller Schooler, I'm keen to amass video clips about the concentric hierarchy of polyhedra, a simple language game involving an assortment of shapes and their relationships. There're lots of artistically distinct styles and scenarios in which this information might appear. Think of Sesame Street and all the distinct treatments of various key topics (e.g. the letter A) have received over the years.
Given my proposal for a 45 minute presentation at OSCON 2005 has been accepted (OSCON = O'Reilly's Open Source Convention), there's an opportunity here to screen some of these clips, with attribution to the relevant individuals, corporations, universities. Maybe the Pentagon Channel wants to put out a few teasers.
Putting on my investment banker hat for a sec, I'd say here's a good way to earn a return. Groups contributing to the Fuller School and by extension to world game, are likely to gain credibility and strengthen their relative positions and currencies for the future. That's just my personal assessment, but it's far from being an uninformed opinion.