Q:“I thought I understood tags, until I looked at the tag management page. What are all these tag types, like suggested and rejected?”Rejected: You can enter a tag in the Rejected Tags area that you don't want anyone to use. For instance, if you have a Global Warming channel, you might want to ban the tag "myth." If a user tried to use that tag on a video, the tag would be rejected. In addition, the tag would be stripped from an incoming video.
Suggested Tags: If you want to help your users tag videos, you can enter a list of tags to suggest to them when they click the Tag tab on the video player. If they're watching a global warming video and then they click tag, they might get a list of tags that would be appropriate like glaciers or greenhouse effect but they could still enter a tag of their choice.
Tags with Aliases: If you want to standardize the tags used on your site's videos, you can use aliases. If you enter glaciers as an alias for glacier, then when a user tries to tag a clip with glaciers, it'll revert to glacier so that tag based playlists and searches will be more accurate.
Frequently Used: That section is pretty self-explanatory. It lists your most commonly used tags, the number of videos the word has been used on, and the number of people who used it on a video.
Categories: A category tag is a word which represents a group. You can create a group, a main tag, which has any number of member tags. If you have a dog channel, you could have dog breeds as a group, with individual breed names as members. You can either enter a list of member tags when you create the group or click add to group when looking at an individual tag.