Has anyone tried
pixsy.com ? It's a reverse image search that you can link your flickr, instagram, personal website, etc. to for free, then see where your images are being used across the web. They also will file takedown requests and that sort of thing and split any commissions with you when you get settlements.
A photography group I'm part of here in China recommended it and apparently they've got some pretty good results and decent payouts. I signed up the other day and just got my invite tonight. I found lots of uses of my images in all kinds of weird places, from message boards to weird instagram hashtag aggregators to personal blogs and so on. I filed two takedown requests, one was a major travel site in china using one of my images and another was some company on LinkedIn. If I get any kind of response at all or money out of it I'll update the thread, but just wanted to share that link as it might potentially be a pretty useful tool for people in here.
Also @dhlt I really like that last one you posted, I like the triangle formed with the sky/clouds and the line from the beach.
@mook dope as usual, first and third ones especially.