Development of Creative Commons licenses

["Lorenzo De Tomasi" <lorenzo.detomasi AT creativecommons.it>]

I have some doubts about derivative works and I would like to solve them
with some examples and questions.
- - - - -
If I choose a CC-Attribution license you are free to make derivative works.
"Derivative Work" means a work based upon the Work or upon the Work and
other pre-existing works, such as a translation, musical arrangement,
dramatization, fictionalization, motion picture version, sound recording,
art reproduction, abridgment, condensation, or any other form in which the
Work may be recast, transformed, or adapted, except that a work that
constitutes a Collective Work will not be considered a Derivative Work for
the purpose of this License. For the avoidance of doubt, where the Work is a
musical composition or sound recording, the synchronization of the Work in
timed-relation with a moving image ("synching") will be considered a
Derivative Work for the purpose of this License.
- - - - -
What do you mean exactly with "or any other form in which the Work may be
recast, transformed, or adapted"?
Can you make little modifications, like changing only few words of my
original work? or you can make only substantial modifications?

For example if I take an original text by Richard Stallmann released under a
CC-Attribution, can I change only the words 'software' with the word 'work'
and add the text "This is an article derived from the original work by
Richard Stallmann"?

If you can make only substantial modifications, what exactly is a
substantial modification? What does differentiate a substantial modification
from a little modification?

I can take a whole article under the CC-Attribution and publish it in a
collection followed by an article of comments written by me.
But can I integrate the first article with my comments quoting the parts and
citing the writer each time? like
- - - - -
Tito wrote: "I think bla bla bla"
and I think bla bla bla.
Then Tito says "bla bla bla"
and I say bla bla bla
- - - - -
?

And can I delete every citation of the original author? like
- - - - -
I think bla bla bla [using exactly the same words of Tito] and bla bla bla
[writing original ideas].
- - - - -

Can I use the same text written by Tito to explain exactly the opposite?
- - - - -
I dont think that bla bla bla [where bla bla bla is the original text by
Tito]
- - - - -

Other examples and questions may follow :-)

Thanks for your help.
Ciao,
Lorenzo