Many viruses face a choice after they have infected their hosts: to replicate quickly, killing the cell in the process, or to become dormant and lie in wait. HIV, herpes, and a number of other human viruses behave this way and, in fact, even the viruses that attack bacteria – phages – face similar decisions when invading a cell. What causes a virus to choose dormancy over immediate gratification? Prof. Rotem Sorek and his group in the Weizmann Institute’s Department of Molecular Genetics have now discovered that, during infection, viruses secrete small molecules into their environment that other viruses can pick up and “read.” In this way, they can actually coordinate their attack, turning simple messages into a fairly sophisticated strategy.