It's a four factor test (but the second factor rarely counts). the purpose and character of your use the nature of the copyrighted work the amoun

It's a four factor test (but the second factor rarely counts). the purpose and character of your use the nature of the copyrighted work the amount and substantiality of the portion taken, and the effect of the use upon the potential market. The court found that Google copied the entirety of the work into their search index, but that this (taking into account the strict result snippet restrictions) didn't effect the market because no one would decide they didn't need the book now they had the snippet.