It's not just amongst your friends, but Google already offers this in the latest versions of Android. It says "Suspected spam call" below the number during the incoming call.
AT&T's seemed to work OK for the first few months. Then calls started slipping through. Then AT&T started trying to sell me an "enhanced" version for $x/month.
So now the telcos have found another way to make money from phone spam.
AT&T's seemed to work OK for the first few months. Then calls started slipping through. Then AT&T started trying to sell me an "enhanced" version for $x/month.
So now the telcos have found another way to make money from phone spam.