Photobucket Advances Tagging Concept

The media-sharing site Photobucket is introducing a search mechanism that lets users append labels to specific faces and objects in photos.

The new 'tagging' feature, expected to launch Thursday, also lets users easily link to external sites such as online references on a landmark photographed.

Tagging represents a way to organize photos, video and other information with multiple descriptive words. On Google Inc.'s YouTube, for instance, video of a python attacking rabbit gets tags that include "python, snake, rabbit, reptile, eat, devour, food, chain", helping to guide people who search the site looking for any of those things.

Until now Photobucket, a unit of News Corp.'s Fox Interactive Media, enabled searches of photo headlines. But someone searching for "bridge" wouldn't find a photo called "View of Golden Gate". Tagging allows people to attach both "bridge" and "Golden Gate" to their photos.

And users will be able to specify where in the photo the bridge is located. Likewise, tags can be attached to specific faces in a group photo.

With rival Flickr from Yahoo Inc., users must list every name as a tag for the entire photo, though Photobucket's new feature is like Flickr's Notes, which lets users attach a non-searchable note to part of a photo.

Alex Welch, co-founder of Photobucket, said he had been skeptical of tagging because many users add scores of meaningless descriptors in hopes of drawing more visitors. He said Photobucket was waiting for technology that gave tags more meaning.

When users embed Photobucket photos into other sites – such as personal profile pages at its sister site MySpace – the tags and attached links will follow them there.