I don't know. People timestamp & broadcast other people's notes. Labeling would be pretty on par with those actions, I think.

That can be argued against hashtagging too. Labeling is already strictly better than that. Many people like to curate and categorize things, and, as I said, reactions are already that to some extent except they are more cryptic, uglier and less useful. And there may be other benefits, I'm just saying there is room for experimentation. We can also watch to see what Pubky does and perhaps copy them later.