Tumblr really stumbled into a beautiful feature with the whole "tags are separated from the main post" (as they should be, they're metadata) + "tags can be as long as entire tweets" thing. They make a really nice form of textual subvocalization/whisper mode/aside/whatever (they're flexible!).
I keep finding myself wanting to make such asides on other sites and find myself subtly irritated that I can't. I wanna elaborate in a way that is diminished compared to the main post!