When saving an article to Connotea, users "tagged" the article with keywords of their choice which they could later use to find it again.

A narrow folksonomy, on the other hand, occurs when a few users, primarily the content creator, tag an object with a limited number of terms.

A Memo function allows users to tag an enjoyable song and refer back to the title or artist before heading for the music store.

Like Facebook's regular tagging feature, though, users can tag images with their friends' names without prior consent.

Delicious is a social bookmarking service that allows users to tag, save, manage and share Web pages from a centralized source.

The best systems allow users to tag certain parts of the document to create content specific comments.

Anonymous users cannot tag, comment, or rate resources.

This allows users to tag particular locations with images and other information.

For instance, if a photo contains a user's friend, then the user can tag the friend in the photo.

Any user can tag their comment with relevant terms.