If you are like most of us, you want the people who are calling your cell phone to be important. That is why Truecaller’s Call Filter is a favorite feature, Incoming calls that are blacklisted on a Truecaller user’s Call Filter, will automatically be blocked or will warn the Truecaller user not to pick up the phone. Truecaller not only helps protect your smartphone from unwanted calls, but it also warns other users that a number is a spam number.