You can skip to the closest key frame in a youtube video by supplying the time you wish to jump to as part of the URL. This is quite handy for sending someone a video where you want them to see a specific part. Instead of sending a link and saying jump ahead to 3 minutes and 14 seconds, you can just send them a link that does it for them.
Add the following to any youtube video URL:
Jump right to the Predator and his warcry near the end of the new Predator remake…
http://www.youtube.com/watch?v=dSbHxcLiExw#t=1m32s
Mark Shuttleworth introducing the next release of Ubuntu, Lucid Linux…
http://www.youtube.com/watch?v=7yNW4fnGPDk#t=3m7s
Yo dawg I heard you like memes…
http://www.youtube.com/watch?v=N-hS6TQ7tfc#t=1m28s