Scientists have known for decades that cells readily communicate with each other. To send signals close by, a communicative cell can nestle up to a neighbor that has the lock into which its key fits (yes that is a euphemism - a euphemism for ligand-receptor binding. To talk to other cells they aren’t directly touching, cells can release substances such as hormones). These substances enter the circulatory system and eventually are sensed by other groups of cells that can respond to that specific signal. We pretty much thought those were the only two broad ways that cells could talk to each other by directly touching or by releasing signaling molecules. However, in the 80s, a group of scientists first described tiny spheres, or vesicles, inside cells in a laboratory[1]. They noticed that these vesicles were eventually expelled into the cell…