Fair use is a legal doctrine that promotes freedom of expression by permitting the unlicensed use of copyright-protected works in certain circumstances. Section 107 of the Copyright Act provides the statutory framework for determining whether something is a fair use and identifies certain types of uses—such as criticism, comment, news reporting, teaching, scholarship, and research—as examples of activities that may qualify as fair use. (Copyright.gov)
The Fair Use Doctrine is ambiguous, and it can be difficult to interpret what types of use constitute as "fair use." To help determine Fair Use, one must apply these four factors:
To help answer questions about linking and framing and fair use, please consider the following resources: Stanford University has an excellent guide to copyright and fair use, including this page about linking.
Here, the following cases are mentioned:
The US Copyright Office has an index of fair use-related court decisions, providing one-page briefs about a given case and whether or not fair-use applies. Look for the “Search Index” button under the photo on the page.
Selecting "computer program" and "internet/digitization" from the categories list shows several cases which apply to linking and/or framing questions (including Kelly and Perfect 10, above) In almost every circumstance, the court used the four-factor test for determining fair use… and so it may be helpful to read the rationale presented to describe that process. For example, see: Walsh v Townsquare Media Inc, involving embedded Instagram posts.