The constant dynamic movement of synapses and their components has emerged in the last decades as a key feature of synaptic transmission and its plasticity. Intramolecular protein movements drive conformation changes important to transduce transmitter binding into signaling. Constant cytoskeletal rearrangements power synapse shape movements. Vesicular trafficking at the pre- and postsynapse underlies transmitter release and receptor traffic between the cell surface and intracellular compartments, respectively. Receptor movement in the plane of the plasma membrane by thermally powered Brownian diffusion movement and reversible trapping by receptor-scaffold interactions has emerged as the main mechanism to dynamically organize the synaptic membrane in nanoscale domains. We will discuss here the different conceptual and methodological advances that have led to a rethinking of the synapse as an organelle whose function is tightly linked to its dynamic organization.