Sorry to keep you waiting. You'd have to wait a lot longer if we were to
get lawyers involved to generate an "official" license in writing, but the
gist of our position is this:
NELL's knowledge is free for anyone to use for any lawful and
non-commercial purpose, and we provie it on on a strictly as-is basis.
We make no claim about its correctness or appropriateness for any purpose,
we'll do whatever we need to do if some part of it is somehow not in
compliance with applicable laws, and we will not be held liable if anyone
using this data runs into any trouble because of it.
And we'd certainly appreciate being mentioned if it winds up playing an
important role in some other project or endeavor. A link to the website
(http://rtw.ml.cmu.edu/) would be great, and we also have a number of
publications at http://rtw.ml.cmu.edu/rtw/publications if there is a need
for a proper citation. The AAAI10 one, "Toward an Architecture for
Never-Ending Language Learning", is the most recent one that discusses the
core project.