I have no problem with the creative commons system but I don't know much about it.
If I understand it, it's a way of specifying a range of uses that a picture can be used for by other people. That's all well and good if you want to put your work out there for free but I don't.
My picture library may very well be part my pension when I'm too old to drag my carcass in and out of schools anymore.
I already sell a small number of pictures as it is without any particular marketing, but in the future I want to make a proper job of it, so the last thing I want to do is jeopardise that by handing my work out free to all and sundry.
The pictures I post up on the internet are only small, relatively useless images when it comes to printing, but the files I keep here are much more capable.