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Flash Cookies and Internet Privacy
The struggle between Internet marketers and viewers who wish to keep their Web surfing habits private has escalated again. A recent technological trick of Internet marketing is called Local Shared Objects (LSO) or Flash cookies.

Marketers want to know what people look at when they are online so that they can target their Web ads better. They want to "personalize" the ads that you see and they want to find out which ads attract the most attention. A primary method of obtaining this sort of information has been the tracking cookie. However, more and more computer users are blocking or deleting cookies. Many of the leading anti-spyware programs also delete tracking cookies. To combat this consumer resistance, marketing firms are using a diiferent form of tracking cookie that uses Adobe Flash.

The Flash Cookie and How It Works

Flash cookies use a feature of the Adobe Flash application called local Shared Objects. Use of Flash movies on Web pages is widespread and a very large majority of Web viewers have Flash players on their systems. (Adobe says 98%.) Internet Explorer comes with a Flash ActiveX component and plug-ins are easily available for the other major browsers.Thus most Web viewers can be reached by this new method.

Skipping the technical details, here is a brief idea of how the method works. When a Web page contains an ad in Flash format that is appropriately coded, a file can be placed on the viewer's computer that functions much like a cookie. However, none of the present standard methods of cookie control will detect the file. This type of file typically has the extension SOL and can be located in a variety of places, sometimes a sub-directory (Windows XP) of
\Documents and Settings\{User Name}\Application Data\Macromedia\Flash Player\.
In Windows Vista/7, the location is
\Users\{User Name}\AppData\Roaming\Macromedia\Flash Player\

Finding Files Used for Flash Cookies

Doing a search on your computer for files with the extension .sol will reveal the presence of files created from a Flash local shared object, provided that the file location has been indexed. The figure below shows what I found in one folder on one of my computers. Each of the subfolders shown contains a file (not shown) with extension SOL.

List of Flash cookies 

From their names, it is clear that some of these entries come from Web ads. However, in the same way that many cookies serve legitimate and useful purposes so do some of these files. Also, other members of the Flash MX suite such as Dreamweaver may use local shared objects. Thus, persistent files are by no means only due to advertising but may be present for a variety of legitimate reasons. While it may be tempting to stop tracking by using the brute force method of deleting SOL files, there is a better way.

Managing Flash Cookie Files

Fortunately, Adobe has provided a site where the settings for Flash players can be configured so that tracking can be controlled. There are a number of pages where settings on your local computer can be adjusted. Examples of several configuration panels are given below.

Go to this page to see what what objects are already on your computer and to delete them if desired. The figure below shows an example panel. There is a slide bar for setting the amount of storage allowed and it can be put to "None" by sliding all the way left. If you visit these sites again (perhaps inadvertently) you may get a popup asking if they can have some space. To avoid any messages, put a check in "Never ask again".

Adobe Flash cookie settings

To control the amount of space on your computer that sites can use on future visits, go here. An example of the control panel is shown below. Again there is a slide bar that can be put to "None". This may result in sites asking for more space unless you check the box next to "Never ask again". Just as blocking all cookies can stop some desirable sites, checking this box may block some legitimate functions such as shopping carts. There is a box by, "Allow third-party Flash content to store login information and other data on your computer". I would suggest removing the check. Whether you wish to allow the "Store common Flash components to reduce download times" depends on your personal preferences.

Flash cookie settings manager


Tracking Flash cookies already downloaded to your computer via ads in Flash format can be removed with the settings manager at the Adobe site. Repeat downloads from sites already visited can also be blocked. However, future downloads of tracking files from sites not previously visited can only be blocked in a global sense. The type of fine-tuned control available for browser cookies is not yet present.

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