Okay, so it's a given that stealing bandwidth is bad form and downright rude, but what is it? How do you know if you or someone is stealing bandwidth?
One way to determine this is to look at the source code of a page. Look for references to images, sounds and other multi-media files. If the reference is of the form shown below (this is a local reference), then you most likely do not have an instance of bandwidth stealing:
<IMG SRC="foldername/animage.jpg">
As you can see, the URL of the image does NOT contain the http (or ftp) and does not contain a web site name. This means the image is taken from the current web site and is not stealing.
Unless, that is, a BASE HREF tag has been used. This is specified in the document header (between the <HEAD> and </HEAD> tags, and takes the form:
<BASE HREF="http://www.someotherwebsite.com/">
This would define all references which are local to be on the other web site's URL. Thus, it would appear from the IMG SRC tags that the images were locally references, but the BASE HREF is changing them to the other web site.
More explicitly (and more usually), you can spot bandwidth stealing references because they take the form shown below:
<IMG SRC="http://www.anyoldsite.com/animage.gif">
Than you may have a case of stolen bandwidth. I say MAY because although this reference is indeed loading an image from another web site, the webmaster may have permission, he may own the other web site or the reference could even be to the same web site.
One of the most common types (at least that I've seen) of bandwidth stealing is that of linking to images in forums. I experienced this personally after I created a very comprehensive September 11th memorial website with lots of interesting graphics. I noticed that my web site was getting a very large amount of traffic (several dozen gigabytes) and I wondered why.
I was alarmed because bandwidth costs money, and my memorial web site was generating an incredible amount of traffic. This could, if not stopped, have cost me several hundred dollars.
I checked my log files and found most of the traffic was from a few images - less than a dozen of them. All of the images were being loaded from a specific web site. I investigated and determined that a number of people were making their postings look better by linking to my images. Since tens of thousands of people were reading those posts, the images were being loaded off my server over a hundred thousand times a month.
I blocked those web sites in my htaccess file and solved that issue.
Another common source of bandwidth stealing is using images in guestbooks. You might find a great image somewhere in the web and want to show that in your guestbook entry, so you simply include the IMG SRC with the image name. Seems harmless enough, until you understand that someone pays for that image load over and over again.
I've seen other examples of bandwidth stealing. Someone creates a site and wants to include some cool graphics. He simply links to those on another website without thinking about it (it's harmless, right?) He has now cost someone some money without even really understanding why or even that he has done so.
So how do you keep from stealing bandwidth? Simply make sure that all references to images, multi-media, zip files and any other objects are local to your own web site. Personally, that is all that I do. In fact, I make a habit of this for another reason: the web changes quickly, and just because an image exists today doesn't mean it will be there tomorrow. If the image is actually contained on my own web site, then I can be sure that it will not be deleted or moved. Thus, my sites tend to have few, if any, broken image references (atttempts to display images that fail).
Unless otherwise noted, all photos and text is Copyright © Richard G Lowe, Jr.