Unwanted advertising — or spam — is obviously nothing new. We’ve had it all the way back to when we got leaflets and brochures in the mail. Now that we are more online and also on our smartphones, spam is annoying the hell out of us in our emails and on our phones. While email services like Gmail have a pretty robust email spam filtering system in place, the same cannot really be said for our phone calls. So how do you block spam calls on the iPhone?