Apple announced iOS 7 a few hours ago, and it does a bunch of new things that we're going to cover over a few news posts. The first of which, is the option to combat against mobile spam with the ability to block calls and texts from specific numbers.
Apple talked about the new privacy option during their WWDC keynote, saying that the next-gen mobile OS includes "Phone, FaceTime and Messages blocking to prevent specific people from being able to contact you". I think this feature is going to be great for those stalker exes you might have, or those friends who drunk dial you on a Friday or Saturday night.
I'm sure Apple will continue to work with this new feature and give it more power, which is something we should see before iOS 7 debuts later in the fall.