Ostensibly these are for searching/categorization, but people often use them to write out responses to posts so that their followers can reblog the it without bringing their comment along (Tumblr just puts all replies into a single extended post so it’s a bit cumbersome to have long comment chains). The tags are visible in the “notes” section of the post, so people can still see it.

wtf. and they say the fediverse is confusing…