A key element of Fair Use is how "transformative" your new work is; in other words, how much you have "altered the original with new expression, meaning, or message". Merely reacting to something, or providing commentary on what is happening is not sufficiently transformative. Although reactions may become more transformative by offering clear criticsm or review, or by sufficiently altering its expression with your own jokes, editing, or presentation. Oversimplified, the more creative effort you put in, the more likely it is to be Fair Use.
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