Constant Content

I have seen many posts about stolen content here on CC. I am wondering how this content was located? I would love to know how I could check to see if any of my articles have been unjustly borrowed (apart from when someone else tells me!).

Also, does anyone know of a way to keep track of an article that has been sold with use or usage rights to ensure that the buyer is adhering to the rules and not deleting bylines etc.

I tried Copyscape but you need a physical website location for the content. If I use the URL of the CC page the article resides on Copyscape does not seem to be able to locate the article (I tested this with sold articles I know have been used online and there was still no trace).

Any help?

* Google Alerts: copy and paste a unique phrase or two from your content and receive emails from Google when found. (Free but I'm not sure how effective it is)
* CopySentry: monitors content for a fee (the best but expensive if you have a lot of content)
* Fairshare.cc: monitors up to 20 articles (flukey)
* Plagium: copy and paste text to find matches (free but you have to do it manually and it doesn't track for you. It's good for spot checking though)

Thanks Celeste!