True caller is a good idea, we know that with true caller we can find unknown numbers id and we can search numbers for finding whose that number belongs to, here in this point of view true caller and we need to take care about that, enemy persons also findout caller id and do harm for that numbered persons that who dont like that persons, its very dangerous. and I heard that true caller servers saves our contacts and names in his server that who is not registering in truecaller also. example we saves our family members mobile numbers in our mobile its common, then true caller can saves those numbers and names of our family members and all the numbers and names in our contact list. without registering those people in truecaller. true caller need to take care about this feature, thats a good feature but in feature we may face many security problems.