Divide, differentiate or die? Making decisions at the right time and place is what defines a cell's behavior and is particularly critical for stem cells of an developing organisms. Decision making relies on how information is processed by networks of signaling proteins. The teams around Christian Schröter from the Max Planck Institute of Molecular Physiology in Dortmund  and Luis Morelli from the Instituto de Investigacion en Biomedicina de Buenos Aires (IBioBa) have now revealed for the first time, that ERK, a key player in stem cell signaling processes information through fast activity pulses. The duration of the pulsing interval, might encode information essential for divergent fate decision in stem cell cultures.