Turn on Green Robot, a new experiment in Gmail Labs, and you'll see a robot icon next to people who are currently using Android phones. In the case below, Shirley is online with Android, Nicolle R. is using regular Gmail chat, and Chris I. is currently away but also on Android. Slatka is not an angry robot — she's online with Android but currently busy.
These icons can help you decide whether to tailor your conversation to the type of device that your chat buddy is using. For example, when you know the guy on the other end is using his Android phone, you may decide to send shorter, more concise chat messages.
When your chat buddies log into Gmail, their presence icons will revert to the traditional red, green, and orange status bubbles. In addition, if your chat buddy happens to be logged into both Gmail and Android chat then the traditional Gmail status icons will be shown. Try it out and let us know what you think.