Multi-object spectroscopy (MOS) is a crucial capability for measuring the properties of statistically significant samples of stellar or galaxy populations.  Such a capability has become more common on ground-based facilities via fiber-fed or slit mask spectrographs.  For the first time, the multiplexing advantage of MOS will be combined with the superior sensitivity of a space-based mission thanks to the NIRSpec instrument on JWST.  By means of its Micro-shutter Assembly (MSA), NIRSpec will enable spectroscopy at 1-5 microns of >50 sources in a single pointing, revolutionizing such disparate fields as galaxy formation, cosmology, star formation, and stellar evolution.  At the same time, observing with a fixed grid of apertures brings unique challenges to both observation planning and data calibration. I will review the operational characteristics of the MSA observing mode, and provide an overview of the proposal planning, calibration pipeline, and analysis tools we are developing to help users maximize science from MSA data.