
I took the plunge a little while ago and went for issuing my Flickr-hosted photos under the least restrictive CC licence (a simple Attribution one), with the intention of allowing people to make use of them as they see fit. This essentially means that anyone can make use of the images without having to ask my permission, so long as they give a credit and (ideally) some kind of link back to the original work. The theory is that the more they are opened up, the more likely it is that other people will make use of them. The more others make use of them, the more my name or work gets spread around, bringing more visitors back my way (which is basically the essence of Creative Commons licences).
It's not immediately easy to keep a track on who does actually use these items. Ideally, whenever somebody uses your work, they would tell you and you'd be able to keep track of what has been used. This would add more levels of restriction to the use of the licensed work though, which runs counter to what a culture of sharing is trying to encourage. Instead, I believe that good 'CC practice' is to tell someone when you've used their work, expecting nothing back in return but embracing it when someone tells you 'Hey, I did something with your picture/tune/words (delete as appropriate)'. Admittedly I've not done it that often when I've used another person's CC-ed works, but have had a positive response on the occasions that I have.
Stumbling over my Flickr stats the other day, I found out that one of my pictures had indeed been used in the manner I was making them available for - in the legal parlance, a 'derivative work' had been created. Having never previously made any knowing contributions to the culture of steampunk, I was intrigued to find that a photo of a Nagano ski-slope I'd taken had made its way into an image at steampunkwallpaper.com - a place I'd never knowingly have stumbled across. There's an intriguing element added to the original picture that I would have loved to have seen first time around!
It's not immediately easy to keep a track on who does actually use these items. Ideally, whenever somebody uses your work, they would tell you and you'd be able to keep track of what has been used. This would add more levels of restriction to the use of the licensed work though, which runs counter to what a culture of sharing is trying to encourage. Instead, I believe that good 'CC practice' is to tell someone when you've used their work, expecting nothing back in return but embracing it when someone tells you 'Hey, I did something with your picture/tune/words (delete as appropriate)'. Admittedly I've not done it that often when I've used another person's CC-ed works, but have had a positive response on the occasions that I have.

Have you had any interesting re-uses made of your work?