The YouTube API’s standard feeds are a great way to expose your users to
the best of what YouTube has to offer. To compliment the existing standard video feeds,
which contain lists of individual videos that meet certain criteria
(the top rated videos in the United States for the current day, for instance), we’re happy to introduce a new set of standard channel feeds.
While standard video feeds contain lists of videos, standard channel feeds contain lists of channels, or user accounts. The two types of standard channel feeds are most_viewed and most_subscribed, and just like with video feeds you can narrow down your results even further with time, region, and category or user type
parameters. For example, the URL for requesting the most viewed
channels with videos related to music in Great Britain for the past week
is http://gdata.youtube.com/feeds/api/channelstandardfeeds/GB/most_viewed/-/Music?v=2&time=this_week. Each entry in a standard channel feed provides detailed information about a specific YouTube channel, including a element with info on how many comments, videos, and views that channel has received.
Once you have these lists of channels, a natural next step would be to allow your logged-in users to subscribe to a given channel or view a list of videos uploaded in that channel.
Standard channel feeds are only available in version 2 of the YouTube API, which will soon be the default version in the production environment. In the meantime, be sure to explicitly specify that you want to use version 2 when making your YouTube API requests.