I am at one of these agencies. This includes a pause on scientific publications to journals

Reddit userbase absolutely skyrocketed when Obama (then president) did an AMA. The site was never quite the same after that

the Chinese state is censoring and fencing off some of the content there as a result. Source?

tiktok has(d) developed into a hivemind where tens of millions of people (or more?) can be a part of a discussion. This made it easy for trends to spread rapidly, such as deciding where to migrate with the impending tiktok ban. From my own experience on tiktok, the last few weeks there was much discussion of where to go, and it appears the hivemind settled on rednote.