@eigen so i acknowledge there is *some* overlap with bookmarks here
bookmarks: privately mark something, usually so i can find it in search. maybe i like it, maybe i dislike it, maybe i want to follow-up later
fave: stuff i love (notifies the author, bumps the post up in the Explore tab)
missing "acknowledge"-level button: an "i saw this" button, usually ephemeral, rarely a post i would need to find in search in 6 months time