Video channels

A way to categorize web content is by association of so-called tags (e. g. technorati. The idea is not new at all - libraries have done this for ages, with the difference that their tags are controlled (also known as keywords). A first web-based approach was Glimpse, and other approaches towards website indexing are also known.

Some tagging networks (some of them also known as social bookmarking sites) can be found here. Tags may help in discovering interesting sources, provided that users explicitly add tags to their content (e. g. in weblogs). However, it seems to me that it's a rather tedious process, at least when textual content is concerned, given that most sites include a search function (based on previous indexing) that provides satisfying (although not perfect) results.

When it comes down to non-textual content, tags or (video) channels seem to be more essential, as found in YouTube and Yahoo. A comparison of their approaches shows that YouTube's channels are more social and blog-like, allowing to

view subscribers, connect with them, leave comments in channels, send messages, add the channel owner as a friend

To sum up, YouTube has three ways of indexing content, namely

• categories with a handful of keywords and the possibility to associate tags,
  
• channels, which can be thought of as an individual media homepage with the additional possibility to connect to users, leave comments and, of course, subscribing to them
  
• groups which seem to be like a discussion board which can be associated to categories.
  

Some more useful information about YouTube can be found here. If interested about the story behind this service, read this. In order to interface with the service on the developing side, some APIs are offered. I am wondering whether channel subscription is also included.