Aral Balkan current #indiewebcamp rough consensus is to use URLs as nouns, pingback (or webmention) as notification infrastructure.

Personally I am doing some rather more complex stuff where I author notes using @-names, which get parsed by @cassisjs into .h-x-username twitter.com-linked anchors, then I transform those into .h-card’s with data either from my contacts DB (at the mo mirrored from my personal CardDAV share) or from the identengine.com API for people I don’t know. Then all the links in a note get sent pingbacks.

Fat chance of twitter implementing that though ;)