How could you know that the people locator you are going to use would be a best people locator? There is a very simple method to confirm this. There are almost 1.6 billion people using the Internet and an ideal people locator should have database including all these people. But in practicality, it is not possible. So, you should see that if the people locator is at least contains the database of as much the people as there are in your region like in US. This way you can decide whether your people locator is the best people locator around or not.