Motion media (such as movies): You can use up to 3 minutes, or 10 percent of the original production, whichever is less.
Text: With text you’re allowed to use up to 10 percent, or 1,000 words without permission, whichever is less.
Poetry: Poetry is a little different. You can use entire poems, up to 250 words, no more than three poems per poet, or no more than five poems from a single anthology. If a poem is longer than 250 words, use is limited to 250 words from the selection, no more than three excerpts by a poet, or no more than five excerpts by different poets.
Music, lyrics, and music videos: Like other forms of content, with music, lyrics, and music videos, you can use up to 10 percent of the original work — not to exceed 30 seconds in the case of video. Also note that you may not alter a work to change the basic melody or character of the work.
Illustrations and photographs: Usage for illustrations and photographs is limited to not more than 10 percent of the total number of images on your site, or 15 images, whichever is less. No more than five images may be used from a single artist or photographer.
Numerical data sets: You can use up to 10 percent, or 2,500 field or cell entries, whichever is less, from a copyrighted database or data table.