First if all I thaugt that the truecaller is fake application and shows random name but later I came to know that truecaller is true by nature and it actually works and makes your task easy.
The concept of reading contacts from phone and keeping in their data base and whenever required related information is provided. This app can give or track the unknown person whose calling you as well as users have a choice to spam or block numbers which come from service providers.
Loaded with various features and functions including privacy protection its a very usefull app in day to day life. Especially for bussiness persons as they have large contact list. Which will benifit others in some or other way.