首先是链接:《Fair Use on the Internet》
A Report for US Congress, by Christopher Alan Jennings, Legislative Attorney, American Law Division.

1、以下会节录上述文章中的一些部分,并且加一些简单的评论,希望what I have done can find the fair use defence wherever in US or in China.所有加了引号而没有跟“[……]”的地方都出自上面的文章,跟了“[……]”的地方,也是转引自上面的文章。“{……}”的地方则是Donnie自己的注释——注释就是注释,其中有一些与主题无太大关系的瞎扯,你可以跳过。

I. 基础{不仅是知识基础,而且是讨论互联网上的合理使用的制度基础}:Four statutory factors to weigh whether a use of copyrighted work is "fair use".

Copyright owners will never enjoy the absolutly exlusive rights over their work since the core objective of copyright law is to "promote the progress of science and useful arts". According to the US statutes and case law, the defense of "fair use", as a privilege but not a right, can be found under the following factors:

Firstly, the purpose and character of the work.

This factor has two primary facets, "whether the use serves a commercial purpose, and whether the new use is transformative. The interesting transformative standard can be reasoned also by the goal of copyright, which is to promote science and the useful arts". "The more transformative the new work, the less will be the signivicance of ther factors, like commercialism, that may wegh against a finding of fair use." [Campbell v. Acuff-Rose Music, Inc., 510 U.S. 569,579 (1994)] Its definition, however, is not subject to exacted. As a general rule, if the new work "merely super sedes the objects of the original creation", it is not transformative, but if it adds sth. new, with a further purpose or different character, altering the first with new expression, meaning, or message," it is transformative.[id, at 579]

Comparing with Chinese legislation, "transformative use" is more flexible than those listed criterions in China Copyright Act, such as "为介绍、评论某一作品或者说明某一问题,在作品中适当引用他人已经发表的作品". A distinct character of Chinese legislation is 求全责备,which emerged from the “爸爸law”心态 of Chinese legal history.{“爸爸law心态”是本人对中国古代法的重要特点——寓教化于惩罚的心理学扯淡,具体参见梁治平等人的精辟论述}。但实际上,法律是很难将所有legitimate的行为都估计到的,而中国的法律体系又至今不承认案件判决的拘束力。“整”(此乃东北方言)得我们遇到“一个馒头引发的血案”(Abbr.: ManTou)所引发的“血案”的时候,不得不望洋兴叹。Suppose the term of "transformative use" existed in Chinese law, Mr. 胡戈 may follow this term and argues that ManTou is a kind of transformative use which "includes criticizing" of Mr. CHEN Kai-Ge’s original work. I myself, actually in a lunch debate with some prominent young lawyers, had raised an argument that ManTou constitutes a kind of “评论”in Chinese law. Nevertheless, no one agree with me even though they believed ManTou would not be found infringement in the US jurisdictions.

Secondly, the nature of copyright work.

The nature of copyright work is based on the theory of hierarchy protection, which recognize that different copyrighted works may not obatain same protection "in which original, creative works are afforded greater protection than derivative works or factual compilations."[See Compbell, 510 U.S. at 579]. In China, there might be no corresponding princile in dealing with fair use disputes.{当然,要查查先,欢迎读者提出有关资料。} Hierarchical protection leads the finding of fair use more concrete.

Another aspect on the concern of "nature of copyright work" is the division of published and unpublished work. Use of an unpublished work weighs more against fair use than that of a published work. So if you disseminate a part of this article, you may not conduct an infringement, but if you disseminate a part of my research proposal that I just worked out with your computer, you may under a dangerous circumstances.

Thirdly, the amount and substantiality of the portion used.

"There are no absolute rules as to how much of a copyrighted work may be copied and still be considered a fair use."[Maxtone-Graham, 803 F.2d at 1263] Both quantitative and qualitative components will be considered by judges. The material used formed a "substantial percentage" of the copyrighted work or where the material was "essentially the heart of" the copyrighted work [See New Era Publications v. Carol Publishing Group, 904 F.2d 152, 158 (2nd Cir. 1990).] may be found a use of unfair. At the same time, only when the it is unnecessary to further the purpose and character of the use, the suited work will be found unfair use. 

Let’s back to ManTou case. There are two important concepts should be clarified. The first is "substantial percentage" is of the copyrighted work but not of the user, Mr. 胡戈’s work. The second is as a critique or ridicule to Mr. 陈凯歌’s movie "无极" or "The Promise" as its English translation {本来我想自己把电影名翻译成“Non Sense”或“Extreme Nothing”,但是害怕被打,所以还是查了一下海报上的翻译}, in my opinion, the extent of copying in ManTou is consistent with what its purpose and character of the use.

Fourthly, effect on the Market value for the original.

This is the most important element of a fair use analysis. {这里具体判决比较多,参见上面链接的文章的第20个注释},at the same time, the judgement of this selement should be in conjunction with the above three criteria.[H.R.Rep.No.83,90th Cong.,1st Sess.33,35(1967).] 鬼佬s, especially American people, are so utilitarian that they believe the most important aim of creating a work is to disseminate it and to make money as much as possible. {这一点,就和俺们中国人不同,我们都是精益求精,用一生的时间才写出个东西,然后还要挖地三尺把它藏起来,有悟性、有胆识或者至少有运气的才能见得到,基本不考虑传播的问题,更不用说考虑市场价值了——参见《九阴真经》、《葵花宝典》等} Under this philosophy, the US Supreme Court stated that &
quot;the only harm to derivatives that need concern us … is the harm of market substitution." "While a ‘work that merely supplants of supersedes another is likely to cause a substantially adverse impact on the potential market of the original,’"…"a transformative work is less likely to do so." 换句话说,the transformative works are not punishable because they will not, generally speaking, cause substantially adverse impacts on the potential market of the copyrighted works.