From the WSJ:

Attributor analyzes the content of clients, who could range from individuals to big media companies, using a technique known as "digital fingerprinting," which determines unique and identifying characteristics of content. It uses these digital fingerprints to search its index of the Web for the content. The company claims to be able to spot a customer's content based on the appearance of as little as a few sentences of text or a few seconds of audio or video. It will provide customers with alerts and a dashboard of identified uses of their content on the Web and the context in which it is used.

Meanwhile, for those of you in Britain, via Susan Kirkland, you can put that big old circle C on your stuff at Copyright Deposit. Although, you might want to be careful how liberal you are with your copyright. Editors might not think it's very cute when you copyright your pitch letters.