I've seen my site copied countless times. There are at least 5 or 6 clones that are blatant knockoffs. There are people that bought the non .com domains of my site, and copied the images I designed, and sections of my html code. There are well known companies that have literally copied some of my content word for word and passed it off as their own. One of the clones is similar to your situation, they created their clone for a different country and language, and have a few hundred thousand users.<p>I stopped caring. I'm by far the leader in the space, and I spend my time ensuring I provide a superior service to the clones. It's actually turned out in the benefit of everyone. It provided motivation, and I worked twice as hard to stay ahead of the pack, so now my site is extremely polished. My users are happy, because they've seen the service continue to improve.<p>So, my advice is not to worry about it, and to focus on providing the best experience for users, so your competitors have no room. However, keep an eye on the competition, and make sure they're not beating you in any area, that might persuade users to switch services.