Presence indicator

A presence indicator is a badge parked on the corner of an avatar, usually about a third of its width, ringed in the surface colour so it stays legible over a photograph of anything. It carries one of a small set of states, and the states are the whole design: available, away, busy, offline, and sometimes out of office. Good implementations give each state a shape as well as a colour, a filled disc against a hollow ring against a dash, because the two most common states are green and red and those are exactly the pair a red-green colour blind reader cannot separate.

What makes the dot harder than it looks is that it is a promise about right now. Every other badge on a screen describes something stored; this one claims a fact about the present moment, and the moment keeps moving. Behind it sits a heartbeat, a timeout that demotes someone to away when the input stops, a rule about what a backgrounded tab means, and a disconnect path for the browser that was closed without saying goodbye. Get those wrong and the dot lies, which is more expensive than it sounds: a green dot that means nothing quietly discredits everything else the product says about other people. If the connection cannot be trusted, a written “last seen 20 minutes ago” is the honest fallback, and it is often the more useful line anyway.

Two different ideas usually share the same dot, and naming them separately is what makes the design tractable. Availability is derived: the system infers it from activity and the person never touches it. Status is declared: someone chooses do not disturb, or in a meeting, or on leave, and expects that choice to be respected. Most systems draw the declared status over the derived one, since a person who says they are busy is busy even while typing. Its sibling signal is the typing indicator, which is about a specific message on its way rather than a standing state, and which expires in seconds where presence persists for hours.

The same promise takes other drawings. In a collaborative document, presence is a coloured caret with a name flag riding beside it, plus a stacked row of faces in the corner reporting who has the file open, and the caret is far more informative than any dot because it says where the person is as well as that they are here. Whatever the shape, the text duty is the same. The dot belongs in the accessible name of the thing it sits on, so a screen reader hears “Rae O., online” rather than a picture and a decoration it has no way to describe.