Tagging your seesmic videos is a topic which has been discussed by the community on many an occasion. When the subject was brought up again a few days ago, I decided to have a play with some code and implemented tagging on the sidebar. Here’s how to use it:

To view all tags, click the “Tags” menu option. This will bring up a “tag cloud” of all the tags, with the most popular tags displayed in a larger font.
Hovering your mouse over any of the tags will show you how many videos have been tagged with that word or phrase.
Clicking on any of the tags will bring up a list of videos tagged with that word or phrase, with the most recent at the top of the list.

When playing a video, clicking the “tags” link displayed in green under the video player will bring up a list of tags associated with that video.
If it’s someone else’s video, you’ll just see a list (see image on right), if it’s your own, you’ll be able to add and remove tags (see image below).

On the image to your left you can see this is my video, so I have a text entry field where I can enter a tag.
Also you can see there’s an X by the side of each tag, which when clicked will remove that tag from the video in question.
Tagging is a great way of finding relevant videos so do have a play and let me know how it goes.
I have some ideas on some cool stuff to add to this functionality - a “my seesmic tags” widget for your blog is one, and an API for others to plug into the tag data.
More ideas welcome of course!
Enjoy.