A big problem for bloggers is that there are always a lot of people that steal your content. In some instances they don’t even try to paraphrase the article so they just copy it word-for-word. I have seen this in many instances with articles that I have written and if you contact those people you’ll often get a funny response like “oh, I didn’t know I was doing that.”
If the site credits the source then that is one thing but there are many people that pass the posts of as their own writing. Copyscape makes it easy to try and find anyone who is copying your posts by looking for other blogs that match a large number of your words.
The service doesn’t cost a thing if you use less than 20 searches per month and after that it will cost $0.05 per search. If you decide to pay that money for the premium service you’ll also be able to choose sites to exclude from the search in case you already know about them.
Copyscape is a great idea and if they offered a flat monthly fee for the premium service I’m sure it would be much more popular. I could then see people creating plug-ins for blogs that make it easy to monitor for plagiarism. At least you’ll be able to track some of your more popular articles at no cost though.