I think once you have sent him a forceful note or two asking him to back off, I would probably drop it. If you want to try and drum up some publicity over it on some other blogs, you might be able to make some headway. But I wouldn't expend lots of energy on him. This sort of thing is akin to people who have their blogs stolen and mirrored by SEO sites using their RSS feeds. You can spend all infinte time and energy chasing after people like this. Alternatively, you can use that same time and energy making new apps and improving existing ones.<p>I haven't looked at both apps, but I would venture to guess that someone who is cutting corners by stealing from other people is probably also not spending a whole lot of time on design, polish, and user experience. Those are things that are hard to copy effectively and a place where you can set yourself apart.