An attempt to provide the basic queries available for YouTube urls.
Usage: http://www.youtube.com/watch?[Queries]
v=
The v parameter specifies the VIDEO_ID
. This field contains an 11-character value that YouTube uses to uniquely identify a video. You can find the video ID for a video in the URL of the web page where you watch that video.
&list=[LIST_ID]
The list parameter specifies the playlist ID when watching a video from a playlist. Entering the ID of a playlist that this video isn't in results in the second video of the playlist getting played next, except if index
is given.
There are some special playlist IDs, for example WL
for the watch later list and RDMM
for the personal music mix (mixes are a special form of playlists).
&index=[INDEX_NO]
The index of the played video in the playlist. Usually causes the video with index+1 getting played next, but there are some special cases when removing videos from the playlist overview on the side or modifying the playlist in other ways while it's being played.
&fmt=
The fmt parameter specifies the return format for the video resolution

&t=
The t parameter allows for deep-linking in the form of #t=1m15s
&hl=
The hl parameter prompts the user(host) to a specific the indicated language
Chinese (Traditional) &hl=zh-TW
Czech &hl=cs-CZ
Dutch &hl=nl-NL
English (Great Britain, Ireland, Australia and New Zealand) &hl=en-GB
English (United States and Canada)* default value &hl=en-US
French &hl=fr-FR
German &hl=de-DE
Italian &hl=it-IT
Japanese &hl=ja-JP
Korean &hl=ko-KR
Polish &hl=pl-PL
Portuguese (Brazil) &hl=pt-BR
Russian &hl=ru-RU
Spanish (Spain) &hl=es-ES
Spanish (Mexico) &hl=es-MX
Swedish &hl=sv-SE
&gclid=
The gclid parameter is used in auto-tagging for Google Ad Words and will show up in the landing page URL when a user arrives at the page from the ad.
&lc=
The lc parameter is used to highlight a specific comment as soon as the page is opened. It can be obtained by copying the URL a comment's publishing date (i.e. "2 weeks ago") links to.
&feature=
The feature parameter is assigned within Youtube to describe certain videos and where display
&feature=watch_response
Any videos in response to a video will have this parameter linked to it. (Assigned within youtube)
&feature=watch_response_rev
The reverse of the above. The "child" video page will have a link to the "parent" page (Assigned within youtube)
&feature=pyv
Promoted Youtube Video (pyv) on a watch page (Must be entered within Google AdWords Editor destination url)
?feature=pyv
Promoted Youtube Video (pyv) on a channel page (Must be entered within Google AdWords Editor destination url)
&kw=
The kw parameter is an indication of keyword insertion. Keyword insertion is an advanced feature that can help make an ad more relevant to a diverse audience. Each time the ad shows, AdWords will automatically replace the code with the keyword that triggered the ad. (Must be entered within Google AdWords Editor destination url)
Unfinished section
&ad=
Advertisement Id assigned to an advertisement ?
&feature=recent_shows
&feature=recentu
&feature=recentlik
Recently Liked ?
&feature=spotlight
&feature=related
&feature=channel
&feature=branded
&feature=aso
&feature=sub
&feature=fvw
&feature=fvwk
&feature=fvhl
&feature=BF
&feature=topvideos
&feature=more_related
&feature=list_related
&feature=player_embedded
&feature=artistob
&feature=youtu.be
&playnext=[1 or 0]
&list=QL
Queue List ?
&shuffle=
&videos=
&playnext_from=
&force_ap=
Sources
https://webapps.stackexchange.com/q/732/40
http://youtube-global.blogspot.com/2008/10/link-to-best-parts-in-your-videos.html
http://en.wikipedia.org/wiki/YouTube#Quality_and_codecs
http://code.google.com/apis/youtube/2.0/reference.html#Localized_Category_Lists
http://www.google.com/support/adwordseditor/bin/answer.py?hl=en&answer=57752
http://adwords.google.com/support/aw/bin/answer.py?hl=en&answer=74996