BitBlocker

The conclusion could also be that format that BitBlocker took was not palatable to the market. When I go to a site that requires that I download a plugin other than the ones I already have installed, I simply move on.

Sure I have Flash and others but truly hate downloading plugins as many of then have proven to do more than you downloaded them to do. Many of them are spyware.

So far the "no right click" code and "cover with a clear picture" seem to be the best options for professional and non-professional photographers. Though the professional should add something like Digimarc or BitBlocker as well. At the professional level, where viewers are truly interested in seeing artwork then you should get a high compliance with the plugin, and more as the software is more widely used and trusted.