Newyorkbrad writes: Keep in mind that this is unexplored territory even for me, but I can give you my impressions of the problems I see with the three licensing options Knol offers. 1) With regard to CC-BY: It's not a question of one license's being more restrictive than the other, exactly. It's that the Share Alike (SA) requirement, which makes the content truly copyleft, can't be added or subtracted in any straightforward way that I can see. (Note that for purposes of simplicity I am lumping together GFDL -- Wikipedia's current licensing standard -- and CC-BY-SA. Their requirements are substantively mostly the same although formally different.) How could you add SA, for example, without being the original licensor, for importing to Wikipedia? How could you subtract it without being the original licensor(s), for importing to Knol? 2) With regard to CC-NC: That content flatly can't be added to Wikipedia, which expressly allows commercial reuse and derivative use. And, with regard to importing to Knol, how could you add the NC requirement without being the original licensor? Indeed, how could you add it at all if you've already granted, in effect, a commercial license by contributing the content to Wikipedia? 3) With regard to "All Rights Reserved," I think the problem of importing and exporting to and from Knol from Wikipedia is obvious. Well, the question here is whether Knol's backers are intending the results of their licensing options. I see no reason to think they don't intend those results. Perhaps I'm wrong about this. If so, I think it might be worthwhile for someone to raise publicly the question of whether Knol's licensing options are intentionally incompatible with Wikipedia's. I don't think it's optimal for the Foundation itself to do this -- it would sound like we're trying to impose our own paradigm on Google, which is not our aim. --Mike