Meta Data

Even people not familiar with computer terms heard of the phrase “meta data”. But what is that really and why is it important ? Well, I'm going to tell you and show you that we are all using meta data quite heavily every day.

Meta data is data about the actual data. A very prominent example are digital still images. The data that most people are aware of and care about is the information of the color and brightness of every pixel in the image file. All together those pixels form the visual image that we are normally interested in.

But the file contains more information than just the pixels. It also contains a set of meta data that describe the image and enhance the mere visual information. There are fields containing the make and model of the camera the images was taken with, the focal length, the aperture time and whether the flash had fired. The orientation of the image, the date & time it was taken, maybe even the latitude and longitude the images was taken at.

All this additinal information is not visible in the image when we look at it but it's contained as so called EXIF meta data in the file. So meta data enriches or enhances the main data and puts it into context. Usually the meta data is much smaller than the data it describes.

If you have the meta data without the main data they describe you can't do much with it. You can't derive the main data from it. Still meta data alone, especially in masses can be a very valuable source of information. Imagine looking at the latitude and longitude meta data of digital images on Flickr. Without knowing the content of the pictures you can tell that certain areas of a city must have some sort of sight just because people take pictures at this place more often than in other places and upload them to Flickr. From the time you could make assumptions whether it's a sight that's popular during the day or rather at night.

In fact most of use meta data unconsciously every day. When you're in a crowd in the street waiting at the traffic light and the crowd starts moving across the street you usually just move with the crowd without checking the road for traffic yourself. That is because you trust the meta information around you and deduct conclusion. If other people are moving across the street somebody at the front must have checked that the traffic light is green and traffic has stopped. So don't know for sure but you trust the meta data and logic whether it's safe to cross the street.

And this happens the whole day without us even knowing. You brain registers meta information and uses logic to draw conclusions and support decisions. And it works pretty good in a high percentage of the cases. Otherwise we wouldn't trust it. If we would have to check all the real data every time we use it, we'd probably be much slower at it. Imagine every pedestrian would explicitly check the traffic conditions before entering the street. There would be an endless queue and jam at every corner.

Meta data can be very helpful and require much less resources to analyze them. This is why intelligence agencies and private businesses are so keen about getting more and more meta data. They are much easier to steal, transmit, store and process than the actual data they are describing. But one can still extract a lot of very valuable information from them. Modern algorithms allow to sift through vast amount of data in milliseconds and draw conclusions from it. Filtering out potential targets for surveillance, attack or targeted advertising.

Unfortunately we're mostly not aware of how much meta information we are emitting. Because it happens automatically when we are using electronic devices. Some of these meta information make our user experience better and we got used to it. For instance when we are calling a website the browser transmits a lot of information beside the mere request URL. It tells which operating system it's running on, which language it's set to, which plugin it supports and many more information. This almost allows for a fingerprint of your individual computer. Without knowing your identity one could follow you through the web just by following your very unique browser finger print. From there it's only a few clicks to correlate that to your real identity. If you for instance login to Facebook using your real name. Then the anonymous browser finger print suddenly has very complete personal profile linked to it.

As you can see, meta data are subtle and everywhere. We emit them with everything we do online and they can reveal much more about us than most of us know. We even use meta data unconsciously every day ourself in our analog world. Now that you know, do something about it 😉

Autor: falko

a *nix nerd

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