Before revision:  As a result, we observe that these two communities are gradually growing apart and more extremism is being found in /r/China _flu. Finally, we examine the spillover effect of the COVID-19 pandemic on user activity across the entire Reddit platform. Our results show significant changes in user activities outside COVID-related communities . In subreddits related to finance, food, and countries / cities, user activity is recovering to the pre-pandemic level in late April and May as countries reopen, but subreddits related to travel and sports remain highly impacted and show lower activity levels than the pre-pandemic period.
After revision:  As a result, we observe that these two communities are gradually growing apart and more extremism is being found in /r/China flu members (around 50\%) that moved to / cities, user activity is recovering to the pre-pandemic level in late April and May as countries reopen, but subreddits related to travel and sports remain highly impacted and show lower activity levels than the pre-pandemic period.