Announced by Ramesh Sarukkai, YouTube Engineer at YouTube blog, "Today at the VidCon 2010 conference, we announced support for videos shot in 4K, meaning that now we support original video resolution from 360p all the way up to 4K. To give some perspective on the size of 4K, the ideal screen size for a 4K video is 25 feet; IMAX movies are projected through two 2k resolution projectors."
You usually watch 4K videos in the IMAX movie theaters, that utilize a 25-feet wide display to exhibit the huge resolution. So yes, it is pretty large and you will find few computer monitors out there which will play such videos in their sizes.
To watch such a video at its native resolution, you have to choose the "Original" option (see image) at the resolution selector. It'll show any video that is more than 1080p in its full glory. You can peruse this playlist of 4K videos from YouTube itself, so that you wont need to search a needle in the haystack.
Because 4K represents the highest quality of video available, there are a few limitations that you should be aware of. First off, video cameras that shoot in 4K aren’t cheap, and projectors that show videos in 4K are typically the size of a small refrigerator. And, as we mentioned, watching these videos on YouTube will require super-fast broadband.
Plotplots.com is the first website designed in India that is dedicated as a por... 
In the age of Radio Mirchis and FMs, I still miss the good old All India Radio's...