When you search for videos throughout all of YouTube, the website allows you to sort the search results by date.
And when you go to an individual channel/user--say, CNN, for example--YouTube allows you to sort that user's entire library by date.
And finally, YouTube also lets you search within specific channels/users. For example, I can go to CNN's YouTube channel and search for Obama, and it will show me search results with Obama.
But youtube does not allow you to sort those user-specific search results by date--or better yet, it doesn't let you search within a specific time frame.
For example: I want to browse CNN's videos about Obama from the year 2011. CNN has 50,000 videos uploaded, and hundreds (if not thousands) of those are clips about Obama.
I can search for Obama. see here: https://www.youtube.com/user/CNN/search?query=obama
But if I want to sort by date, or search within a specific date range, I cannot.