The only thing that can realistically cause a significant spike in tweet activity is a major news event, and major news events are typically unlikely to be neutral.
Critically, the baseline is fairly static, so the extremes in this graph can only be reached by fairly major events that are capable of drowning out the typical everyday tweets.
Critically, the baseline is fairly static, so the extremes in this graph can only be reached by fairly major events that are capable of drowning out the typical everyday tweets.