Most people use their smartphone as their primary camera, because it's always with them and they don't have to carry a second device.
For that reason, camera accessories for smartphones may seem a little backwards, since you're actually carrying around more things. At some point, you might as well just get an actual camera, right?
Generally speaking, though, we're in favour of anything that allows people to do more with the tech they have or push it beyond what it was intended for. And that's what you'll find here.
A few of them are specifically for the iPhone, but Android and Windows Phone users don't need to feel left out, as there are ones here that will work with other smartphones as well.