SmugMug has lots of functionality to protect and brand photos. Watermarks, for instance.
I want to go the other way: most of my photos are Creative Commons licensed. I like them showing up on wikipedia, for instance :-)
On Flickr (which I fled from 3 years ago), it was easy to set a checkbox and it'd show.
The best I can seem to do on SmugMug is to put a note in a custom footer saying "most of 'em are open source CC". Are there other options?