When a call or message is received from an unidentified sender on the user's communication device, the caller identifier application launches a text-based messaging application and causes it to send an “invisible” text-based message to the user's contacts. The message includes the metadata (e.g., telephone number) associated with the call or message that the user received. The invisible message is a short message whose headers are programmed in a particular manner so that the receiving mobile phone acknowledges the receipt of the message and the receiving mobile phone displays no behavior perceptible by the user. When the invisible message is received by the corresponding caller identifier application on one of the user's contact's mobile phone, the application searches the contact's contact list maintained in his or hers contact application. If the metadata provided to the contact's mobile phone is located in the contact list, the contact details (e.g. Name) or the contact card, if available, is sent back to the user's mobile phone in a second invisible message. Upon receiving the second invisible message, the caller identifier application causes some or all of the contact details to be displayed on the user's mobile phone or otherwise presented to the user in any appropriate manner.