Good question. I also have seen a few ads for this website and wondered the same thing. I will look out for the answers, I have heard that there is some sort of test for this, but was a bit wary. I watched a documentary on tv recently that was saying that some websites were asking you to submit a test piece which they published and used from thousands of applicants who were then told they hadn't been successful. It wasn't this website though, so it will be interesting to see what answers that you receive.