If you have customers around the world visiting your site, you want to be certain that they will be able to view your site without any problems, using whatever browser they have available to them. A map showing the most popular web browsers by country can help you determine if your site can be shopped by your target demographic with the browsers they use most.
The only way to ensure that your customers can shop your site using any browser, on any device, anywhere in the world, is to perform thorough and rigorous cross-browser testing. Using a variety of tools, many site owners perform these tests themselves. However, they often run into trouble when trying to address the problems they find.