What Is GistTree?

I posted an article I wrote on HN a few minutes ago and immediately got a notification that someone commented on it. It was a website I've never heard of called GistTree (no link to prevent good SEO coming their way). They seem to have copied the entire content of my article, changed a few words using a thesaurus, and posted it complete with <img> tags pointing to my website. They are pretending like they wrote it.

Has this happened to anyone else here?