During a presentation in London today, Twitter engineer Raffi Krikorian offered up an early glimpse of what Twitter's highly anticipated new annotations feature (or, as he refers to them at one point "Twannotations") will look like. "Threw together a quick, and extremely preliminary view on what @twitterapi has been working on — and what I feel has the ability of being a game-changer on the platform — Annotations," he writes on his Posterous blog. Krikorian also posted his deck, which I'll embed below. Of note, Krikorian says that every tweet annotation will have a "type," and each type can have several attributes. This information will apparently have same "visibility policy" as tweets themselves, which seems to mean "public" unless you set your account to private.