In general, copy the title of the work exactly as it appears on the site. For example, YouTube contains a video that an uploader has labeled “Night of the Comet Widescreen Full Movie 1984.” In your works-cited-list entry, you would therefore provide the title of the work given by the uploader because you’re citing that version of the work, not the original version of the movie, Night of the Comet:

Night of the Comet Widescreen Full Movie 1984. YouTube, uploaded by Jen Dobbins, 20 Sept. 2013, www.youtube.com/watch?v=me4pOQOt20s&t=10s.

It’s important to cite the publication details of the version you consult because parts of the original work could be cut off, distorted by poor recording quality, or even altered in invisible ways. Disambiguation is also important: the same work often appears in multiple versions on video sharing sites. For example, a commercial performed by the comedy team Elaine May and Mike Nichols is posted on YouTube with different titles, and the recordings vary in length by five seconds:

“G E Refrigerators Commercial with Mike Nichols and Elaine May.” YouTube, uploaded by recycledboy, 7 Nov. 2014, www.youtube.com/watch?v=ZPGHQYutitY.

“Elaine Maye and Mike Nicholes Freeze Each Other Out.” YouTube, uploaded by theatrecorner, 18 June 2008, www.youtube.com/watch?v=5DNoNj8JzX4.

Faithful presentation of the work in the list of works cited does not mean that you must refer to the official version of the work in your writing using the uploaded title. If you are writing generally about Chaucer’s Canterbury Tales, you would refer to it as such, even though you may be quoting from an edition titled The Canterbury Tales: Fifteen Tales and the General Prologue or Canterbury Marriage Tales. Similarly, you would refer to Night of the Comet when discussing the movie generally but Night of the Comet Widescreen Full Movie 1984 (where the name of the movie appears in roman font as a title within a title) when referring specifically to the YouTube version or citing from it:

In the movie Night of the Comet, two valley girls fend off zombies and evil scientists to survive the apocalypse. At the start of the film, the narrator says, “The citizens of Earth would get an extra Christmas present this year” (Night 1:09-12).