The DCMA can also be used for small internet artists and writers, who might have noticed that their work has been ripped off and spread without their consent. There are many sample DCMA notice letters out there and if you've noticed that a website has been distributing your copyrighted art, photos, writing or whatever on a website without your consent, you can use this to stop them.
I would recommend that you first send the website a letter explaining that you want them to take down your work and if they don't respond, you can send the DCMA to their ISP and to places like Google, who will remove them from their search index.
Even if they've just put up one of your articles for free or something like that, without linking to you, it can hurt your own website because search engines don't like content that has multiple duplicates and will penalize it in searches. So it's definitely worth weeding out people who do this, even if they are doing it inadvertently.