Legality of Watching Youtube Videos
It is to my understanding that it is illegal for someone to upload copyrighted materials (e.g. full episodes of TV shows) to Youtube without permission (with the exception of fair use). But is it illegal for someone to watch a video that was illegally uploaded, like a full episode of a TV show?
I do not believe that watching an illegally uploaded copy of a video would constitute actual copyright infringement. I realize that there is not definitive authority on this, but I view this issue as being more akin to watching a cover band play someone else's copyrighted music. Playing it may be an infringement, but listening to it would not be.
There is no definitive precedent I know of on the question whether a download is a copy under the copyright law, so you are shooting dice. My personal view, as an electronics engineer besides IP attorney, is you make a copy in a buffer in your computer or smart phone. Even a stream includes buffering. The intent of the Act is to prevent copying by the unlicensed, and even if your device buffers in parts I think that is within the meaning of the Act.
As a practical matter, most likely you will not be caught, but if you are, and YouTube can be subpoenaed to say who downloaded, there will be expensive consequences, in the hundreds or thousands of dollars. Your decision to make.
Licensed in Maryland with offices in Maryland and Oregon. Information here is general, does not create a lawyer-client relationship, and is not a substitute for consulting with an experienced attorney on the specifics of your situation.
To follow up on Mr. Marcus's comment, there is legal precedent that making a temporary copy of online material in your computer's RAM constitute's a "copy" under copyright law, and can be considered infringement. See http://digital-law-online.info/lpdi1.0/treatise20.html.
There is also legal precedent taking the opposite view: http://newmedialaw.proskauer.com/2008/08/20/ram-copying-an-issue-of-more-than-transitory-duration/
Whether watching YouTube videos constitutes infringement thus would depend on (a) the nature of whether/how YouTube videos are transmitted and stored (even temporarily) on your computer, (b) whether there is some sort of license or fair use defense (or other defense) applicable to the viewing, and (c) which court is addressing the issue.
I am an attorney, but I am not YOUR attorney. By providing free, generalized information, I am not entering into an attorney/client relationship with you, nor am I providing legal advice applicable to your particular needs.
Unless there is more to be said here, there is nothing illegal about watching a video that is in a publicly accessible forum. If the material is illegally uploaded, the liability is not in the viewing but in being part of the mechanics of putting the material there.
This is not a legal advice as I do not have an attorney-client privilege with you. You should retain a lawyer before acting on any generally available advice.