1.   An antivirus program is designed to recognize telltale virus signatures and to intercept and destroy the rogue code before it has a chance to infect the computer.

2.   The computers would search recorded tracks of light from the debris of the collisions for the telltale signatures of B quarks and then analyze their behavior.

3.   Infrared sensors can sometimes spot minefields from the air, seeking evidence of ground disturbances or telltale heat signatures given off by buried mines.

4.   Unlike paper documents, it can be difficult to verify authorship of an e-mail, which carries no telltale pen-and-ink signature.