Platelets are the major cellular component of the hemostatic system that controls vessel and wound repair. However, platelets also have a variety of additional functions in inflammatory responses and host defense. The function and structure of the platelet was assumed to be very simple for a long period of time. With more modern tools of investigation such as cDNA arrays and proteomics, we have discovered a cell that is becoming a more sophisticated libero that functions in the classic mechanisms of white blood cells--inflammation and immunity.