If you have anything at all scholarly on your site, or that might be used by high school or college students writing research papers, you might see that the turnitin.com robot has visited & abstracted your pages. I consider it a left-handed compliment.
I just wonder what on Earth they could think is relevant to their purposes on my little site! I've got at most one academic paper, outlining the theory for a cryptographic filesystem I might actually finish implementing some day, and I'm not even sure that's up anymore. But Turnitin keeps coming.
I knew there was at least one bot out there whose purpose was to prevent plagiarism, but I didn't know its name until yesterday when it surfed my site for the first time.
Apparently this bot isn't all it's cracked up to be ... turnitin.com is a service which is marketed to schools and professors. If a paper is somehow "suspect", they can upload the text and 24 hours later get a report from turnitin.com as to whether any of the content is plagiarized from known sources.
Possibly, it is a good idea. However, the turnitin.com reports apparently fail to recognize when a source is properly cited, resulting in people being unfairly accused of plagiarism.