incrediBILL - 4:54 pm on Apr 6, 2012 (gmt 0)
Defending your copyright is a moot point if you employ methods to stop the infringement in the first place. It's obviously not possible to block all infringement, especially when done by hand, but most of the automated infringement is pretty easily thwarted which will save a ton of time worrying about this mess in the first place.
Being proactive about protecting web content has saved me a ton of time that would've been spent being reactive, meaning block scraping and hot linking to avoid sending DMCAs.
Another way to deal with this mess is to use services like Picscout to automate hunting and I've had some success with TinEye as well.