In a recent post on his blog, Agile Learning, Derek Bruff (Director of Vanderbilt's Center for Teaching) describes a technique for Zoom discussions called "ready-set-go." The basic idea is that an instructor poses a question, asks everyone to type a response in the chat window, but tells them wait until instructed to hit "return." After allowing time for everyone to type a response, the instructor says "ready, set, go" and students all hit return at the same time. This way, everyone's responses become visible after having a chance to consider the question independently. In this respect, it is a kind of Zoom equivalent of "think-pair-share," giving everyone a chance to participate in the discussion.
After trying this out a few times, Bruff offers the following suggestions:
Add a visual cue in the text chat before the question, like a series of dashes or periods, so you can easily spot the start of the responses in the chat. Also, ask participants to put their hands up when they’re done typing; when you see enough participant hands in the video boxes, you know it’s time to say “go.”