If you haven't been noticing various websites taking advantage of "tags" yet, you will. This is another one of those things that the website guys have been talking about for so long that they forgot to tell the rest of the world what it is. I'll see if I can fill you in a bit, since they forgot. :-) It is simple and really useful if you know what the point is.

Computers and humans "see" files like pictures, emails and websites in a very different ways. This makes it difficult for a computer to understand what connections the human brain makes to a picture. Let's say I see a picture of a massive oak tree standing in the middle of a field of wild Maine blueberries. The leaves of this ancient oak have reached the peak of their color change and stand out in gold against the sea of green and blue of the low-lieing blueberry bushes. When we look at such a sight, we see beautiful colors and find aesthetic value. We also immediatly recognize the structure of a tree and field.

Thanks to Martin Hapl for making this available for use around the web. This isn't exactly what I was picturing, but it'll do for our purposes. :-)

A computer doesn't see that picture in the same way. It can tell what colors are in in, but unless we tell it a tree is in a field, it doesn't know. We, on the other hand, don't remember the exact computer codes that make up the red colors of the leaves of the tree that it does know immediately upon looking at the picture. You might say we have a communication barrier that has to be crossed. Computer's aren't real smart so it would be beyond their capability to fix this communication problem. In other words, the entire burden of this problem is in the hands of humans, mostly those computer search engine geeks that Google keeps locked in the basement.

So these super-smart computer guys got together to think about the problem and decided that humans would have to tell the computer about the notable items in the picture or other files. It's easy enough for Rachel to tell Josiah, "Hey, I put a couple cokes in the fridge". Shouldn't it be that easy for humans to tell computers, "there's a tree in that picture". So these guys set out on a quest (in the digital sense) to make it possible for you and I to do just that.

The "technology" they came up with is called "tags" or "tagging" or something with the root of "tag". Don't let that word "technology" scare you though. It just means that they solved a computer problem in a new way. So the picture of the tree that we've been using was tagged by Mr. Hapl with the tags "Autumn, tree, Czech Republic and Se?". When I went to flickr to find pictures of a tree, I was able to search the tags for "tree" and this was one of the many that showed up.

Up to this point, we have only discussed the physical elements of the picture and not the emotional response. By telling a computer about the emotions we get from a picture, we yet again improve the chances that we can find what we are looking for.

Thanks to Gini on Flickr for sharing this picture with the world.

I think we've seen enough of the tree. Lets switch to another picture. Who could resist the wiles of a kitten? It is impossible for a computer to quantify the cuteness of a kitten. All it sees in that picture is a bunch of black and white. By using tags like "cute, cuddly and soft" the emotional connections we make with the picture of an adorable kitten become available to the computer. If you would like to explore the emotional connections to pictures, come over here and try out some emotionally connected words in the search. Check out the diffence in the tone of the pictures when you search for the tag "happy" versus "joy" or "angry" versus "anger".

As you have seen, websites like flickr have taken advantage of the tag idea in the service they offer. Other places you will find the idea of tags include the del.icio.us bookmark service and the technorati blog search service. RBC Ministries, providers of Our Daily Bread, are using tags behind the scenes of their upcoming website to help visitors find related content.