The diagram shows a two-sided arrow that represents the continuum of different types of copyright. To the left is traditional copyright, the most restricted form of copyright. Fair Use allows some “wiggle room” for education but can be a challenge. To the right is Public Domain which has no usage restrictions

Using web-based resources responsibly means having a basic understanding of copyright. Most commercial materials on the web including text and multimedia are covered under a traditional copyright license that restricts what a user may do with those materials. Usually, usage is limited to personal use. The Fair Use doctrine does include some wiggle room for educators but is not a full blown overthrow of the copyright laws. Mainly, it provides for a brief, one-time use of a resource within the classroom. 

Hall Davidson's Copyright and Fair Use Guidelines provides some suggestions for what could be considered Fair Use of media resources. 

Copyright Chart

On the other end of the continuum is Public Domain. Works in the public domain have no restrictions as their copyright has expired. This year, after a twenty year copyright extension, works from 1924 have finally entered the public domain. It includes Robert Frost's well known poem, Stopping By Woods on A Snowy Evening. You can learn more here: https://www.smithsonianmag.com/arts-culture/first-time-20-years-copyrighted-works-enter-public-domain-180971016/