The number one point is to recognize the situation as a conflict of interests - everyone wants an immediate answer to his burning question, but nobody wants to

The number one point is to recognize the situation as a conflict of interests - everyone wants an immediate answer to his burning question, but nobody wants to be interrupted to answer somebody else questions. For the team as a whole there is probably some optimal interruption level which is higher than what the interrupted would set and lower than what the interrupter would choose. That is why muting and 'urgent' messages don't work - because people would tend to mute channels too much and on the other hand 'urgent' quickly inflates and everything starts to be urgent. I think a solution to this could be "attention budgets". There are many complications of course - there are times when you don't mind being interrupted and times when you do, and it is taxing to think about it consciously and set your levels. But I would start from attention budgets - this would also be a solution to general spam, but synchronous spam is much worse than asynchronous - so synchronous is a good place to start.