I’m wondering if there should be a set of conventions for people on video calls to indicate acknowledgement without needing to speak or turn the video on. Reactions, and other status indicators, are not available in every service, and the ones that do have it tend to be for getting the speakers attention.
There’s a convention in aviation, at least in recreational aviation that I’m familiar with, that has inspired this thinking. If someone needed to transmit a message over the radio, they will do so by pressing down the push-to-talk button and speaking their message. With VHF radio, only one person can be transmitting at any one time. Everyone one else on that particular wavelength will be able to hear them, but if they tried to transmit, the whole message will be garbled.
So there’s always a bit of caution when there is a need to use the radio. You’re generally advised to wait a few seconds before speaking on the off chance that someone else starts before you. This is also not a medium that grants you a lot of time to talk: messages are usually quite short, and are usually only made when required.
I guess that’s why a convention was developed, where someone operating the radio will indicate acknowledgement by quickly depressing the push-to-talk button. Doing so usually results in a burst of static clearly audible to everyone else on that wavelength. Unlike accidental presses, this quick tap is less than than a second, so there is no mistaking that it was intentional. This makes it perfect for quickly indicating a message was received, just like a thumbs up would if the conversation was face-to-face.
A convention similar to this would be great for videoconferences. Whereas status indicators are not available everywhere, most videoconference software I’ve used have a mute indicator for each participant. Quickly unmuting and muting the mike would pulse this indicator, which is pretty close to the visual equivalent of that burst of static. Done quickly enough, it will indicate intent, and would therefore be a perfect to quickly indicate the message has been received.