The obvious place to test any mobile site, you would think, would be on a mobile device. But, how many devices are we targeting for our site? Depending on the needs of the site, and its owner and users, there could be dozens of devices. For a web app in particular, it’s important to make sure the site works across as many devices as possible, as we want people to buy through that web app, and they won’t buy if the app doesn’t work for them.