1. A method comprising: sending, from a selective forwarding unit (SFU) to each of a plurality of participant computing devices, one or more digital video streams, wherein the SFU stores identifiers of each participant computing device among the plurality of participant computing devices; monitoring, at the SFU, a system load value which estimates a load on the SFU according to any of a plurality of different load metrics; determining that the system load value exceeds a particular load threshold value and, in response, selecting a subset of the identifiers of the plurality of participant computing devices; for each participant computing device that corresponds to one of the identifiers of the subset, disabling one or more of the digital video streams that are sent to the participant computing device from the SFU; in response to disabling one or more of the digital video streams that are sent to the participant computing device of the subset of the plurality of participant computing devices, waiting a particular period of time; after waiting the particular period of time, determining that the system load value is below a second load threshold value and, in response, selecting one or more participant computing devices of the subset of the plurality of participant computing devices; restoring one or more of the disabled digital video streams.