American carriers warn you when you're using a lot of data, but they don't always tell you how to avoid that usage in the first place. Thankfully, they're taking a more proactive stance with the launch of their Know My App site. The CTIA-run page shows the typical data consumption of popular mobile apps and compares it against capped US wireless plans. You'll want to avoid using bandwidth-heavy apps like Netflix when away from WiFi, for instance, but miserly software like Candy Crush Saga is safe even with basic internet service. Know My App won't be of much use to mobile veterans -- or anyone holding on to unlimited data for dear life -- but it could prove vital to newcomers who don't yet know how to keep their wireless bills in check.