Computer allowing, I run a live comment wall in class. Students can text to it in real time. I show it to them from time to time, but mostly only I can see it. The main aim is to give them an anonymous means of asking a question if they are too nervous to put up their hands. This element of it is working well, so far as I can tell. I’ve also been surprised how funny it can be, and also how much I enjoy the sense of real time reaction to what I am saying.
Here’s a smattering of the first 250 or so comments, covering the first 5 weeks (it may take some time to load):
I do find it slightly distracting because it is often moving while I am talking to the class, and it does mean the students can be fiddling with their phones rather than paying attention to me, but I think the gains outweigh those slight disadvantages. I also like the discipline that it imposes: I have to be more interesting than their phone.