I host a small, very low traffic website. One day, the bandwidth shoots through the roof and stays high. The reason? One of the images on a page got added to the .sig of someone in a popular forum. Suddenly thousands of people are fetching the image.
The solution was to filter by referrer header, letting the image be seen by visitors to the actual page, but linking from other sites gets blocked. Note that usually it's best to allow requests that have no referrer header at all, otherwise you'll be blocking some legitimate viewers of your site.
End result: bandwidth back down to the usual, tiny levels. It's not that I cared about people copying the images, I just didn't want to foot the bill for the traffic!
> Note that usually it's best to allow requests that have no referrer header at all, otherwise you'll be blocking some legitimate viewers of your site.
It's just another way that (for some reason) my browser leaks information without asking me if I want to.
It gets switched off now, along with cookies, analytics and most other stuff.
I also respect a site owner's desire to track your referer, and to decide the rules for who gets to access their content. They are (often) a business, and knowing where to focus their efforts to make money is important to them.
I don't respect either side feeling they are owed tracking information, or content, if they aren't willing to respect the other agent's rules and preferences.