And that leaves me wondering if local collaboration - within a school (and my, does that hurt Mr. Unschooly to say), or a comfortably snug geographic zone like a town or city - might be more engaging for the students. Face to face is possible across town, and less so around the globe - and face to face seems, if I get danah right, to matter more to teens.
It is also a question of scale. Is one global collaborative project a year from grades 6 - 12 sufficient? If so (and I'd say "yes," give or take), it is a nice feature, but not any kind of structural shift.