I have a personal blog/website that I believe has some high quality, original content.
I am not trying to make a profit out of it, but I don’t want people to steal my articles, especially since I’ve done weeks of research for writing some of them. Is there some automated tool that checks the web for plagiarists?
It’s impossible for people on the Internet to “steal” your articles; the worst they can do is to copy them without your consent, possibly passing them off as their own. While this is a despicable thing to do, it’s not legally theft since the original works remain in your possession.
That said, RealityChuck’s suggestion of using Google alerts is a good idea. Consider also that if your articles are good enough that random people on the Internet are copying and reposting them, perhaps you should consider submitting them for publication in a professionally run online magazine or other website. It will get you more exposure, you’ll might get paid, and the publisher might take up the burden of chasing after plagiarists.
The most likely way your content will be stolen is by an autoblog - a spam site set up to automatically copy articles and re-publish them laden with ads. Most of the time they’ll advertise themselves to their victims by sending pingbacks or trackbacks to the sites they’ve scraped the articles from.
There is a site called Copyscape that claims to detect copying. I’ve seen many small blogs with a sidebar banner indicating they use it, but never heard a success story.
My suggestion is to include a small signature block in the body of your feature articles, “written by Joe Bloggs on 2014-01-01” or whatever you like, with a link to your About or Contact page. And enable pingbacks and trackbacks on the About page. That way you’ll often receive a pingback from sites that re-publish it.
You can send a DMCA or C&D notice to the web hosts of sites that copy your work. Plagiarism Today explains how.