I find that keeping a clear agenda or format to your meetings helps to keep things on track. You might not have an agenda planned out in the beginning and that'

I find that keeping a clear agenda or format to your meetings helps to keep things on track. You might not have an agenda planned out in the beginning and that's fine, too. It will gradually flesh itself out as meetings progress. And when everyone knows what is going on, there'll be fewer disruptions and diversions. In the rare scenarios when someone is just trolling, as the event organizer, you have to politely take them aside and explain the purpose of the meeting and theme of discussion. Making sure they're aware might be the only miscommunication. At worst, explain how the diversions take away from the meetup. Hopefully, you won't need to go further than this. Note: I started running a meetup and supporting my local tech community over the past year. This is one person's observations.