What's with those infographics?

We keep seeing those infographics that have the "post this to your blog" instructions alongside 'em, such as '"15 Things You Didn't Know About Richard Simmons" - right? Has anyone noticed they're all hosted on a range of dubious-sounding domains? I can't recall them offhand, but they're usually found on treadmillreviews.net (real, with the Richard Simmons one), or other such sites like "betterinsurance" or some such crap.

At one time, I shared one on my blog and the creator(s) of the infographics eventually emailed me and said, "hey want us to email you when we create new infographics you'd be interested in?" I agreed and they started emailing me about ALL their stuff - not just the topics I blog about. But I noticed this strange hosting they always use. I asked them about it via email and I never heard back from them. In fact, I can't recall ever hearing about new infographics from them after I asked.

Does anyone know what they're doing by hosting these infographics on various and shady-sounding domains?