If you have a group of people that all follow the same user, you can get semi-private group messaging by just @reply-ing that user. Others can see it if they go

If you have a group of people that all follow the same user, you can get semi-private group messaging by just @reply-ing that user. Others can see it if they go look for it, but it doesn't pollute the timelines of users who wouldn't care about the message. For instance, in my coworking group, we can all prefix our tweets with @{coworking}, which we all follow. We can all see each others' replies to this common account, but Twitter filters it out for our followers who don't also follow that account.