We've had everything from our logo stolen, content on our site, content from our forums and blogs, our knowledgebase and even one very brave person that even stole my name (and names of some of my staff) and posted on their site that Hands-on was shutting down and that myself and a select group of staff had started a new hosting busienss
Digital content can be protected (images) using watermarks, or using the digimarc.com software. I've used this in the past for some of our published work - really helps in legal cases.
If your content is ever stolen, let google know via this DMCA Violation tools and they'll contact the host and sandbox the sites. Google is VERY helpful (as is copyscape). Contacting the user directly usually resolves things, contacting their host is advised also. Posting publicly I'm not big on doing (unless I've tried a number of contact methods) but it is stolen content - MY content.