As far as I know, the download option is only available at a select few videos on Youtube.
That's interesting - the download option is there on all YouTube videos I try here in UK, including all of Tom's I've checked. The option is a fairly recent addition - only within the past few months, and I presumed is a reaction by YT to the many programs now available for the purpose of downloading YT videos, i.e. "if you can't beat 'em, join 'em!".
Maybe geographic, as Dom suggests, in which case it may soon be rolled out everywhere.
Hmm, are you sure the download option is from Youtube itself? It seems strange that it is available on all the Youtube videos you try.. as the option tends to be available when the owner has given the license (creative commons) to it. For example, with this Boston video it says "License: Standard YouTube-license" below the tags (you have to expand the info box). Can you tell me what it says there, or maybe take a screenshot? This Khan Academy video is an example of a video with creative commons license, it should be available for download in MP4 for everyone. http://www.youtube.com/watch?v=52ZlXsFJULI
I have also tried to use "UK internet" through a web proxy, it didn't change my options.
We should figure this out :)
Edit: "Downloading videos from YouTube is not supported, except for one instance when it is permitted."
http://support.google.com/youtube/bin/a ... swer=56100