Fortunately to date, I've had no-one replicate my google adsense code, but I've been running a number of searches this month on unique sentences from text I've written myself, and have found sites where it's been reused.
I'm not sure how harmful such duplicate content can be to SEO, and whilst most sites I've contacted have taken action and removed the graphics and text they've used without permission, there's others that just ignore all contact. One of them is based in India and uses GoDaddy, but GoDaddy want information that can be hard to obtain before they'll do anything.
I'm sure there's plenty of successful website creators in this forum - what do you do? Just let sleeping dogs lie, or bring out the big guns?