you put name tags on pictures to help easily find them and also many of the social sites like facebook use tagging on photos. This may help you understand it better.

What is Tagging? Using Keyword Tags for Digital Photo Organization

The Old Way: Folders
Until recently, the folder concept was most commonly used as a way of grouping and organizing digital data, but the folder concept has its limitations. The most significant limitation of folders, especially for digital photo organization, is that an item can only be in a single folder at a time without duplicating that item.

For instance, if you have a digital photo of a sunset which was taken at Indian Rocks Beach, Florida on your 2006 vacation, you are faced with the dilemma of whether to put it in a folder for sunsets, a folder for beach photos, or a folder for your 2006 vacation. If you were to put it in all three folders it would certainly be a waste of disk space and create a lot of confusion trying to keep track of multiple copies of the same image. But if you only put the photo into a single folder, you have to decide which folder is the best fit, and this type of decision-making can hinder the organizational process.

The New Way: Tagging
Enter tagging. With the concept of tagging, categorizing that sunset picture is much less of a dilemma⦠you simply tag it with the words sunset, Indian Rocks Beach, 2006 vacation, and any other words which might be appropriate.

The true power of tags is revealed when it comes time to find your photos later. You no longer need to remember which folder you might have put something in. You only need to think of some aspect of the photo that you would have used in a tag. When you search on a tag, all the matching photos associated with that tag can be displayed.

Tags are especially useful for identifying the people in your photos. If you tag every picture with the names belonging every face in the photo, you'll be able to locate all your pictures of a particular person in an instant. You can also combine and exclude tags to further refine your search results. For example, a search for "Suzi" and "puppy" will display all photos of Suzi with a puppy. Exclude "birthday" from the same search query and you'll find all photos of Suzi with a puppy except for those tagged "birthday."

http://graphicssoft.about.com/od/glossary/a/tagging.htm

Thanks for asking the question Goldy and many thanks Zep for such a clear explanation. The topic reinforces my practice of checking the threads here daily. There's always something useful to learn that you didn't even know you should know.

I'm going to sign off now while I tag my photos!

@juneroses,

I'd love to take credit for that explanation but it's copied and pasted from the web site that I linked below it...