For as long as I can remember, status messages have been part of anything online where you can alert people to, well.. your online status. Games, IM services, you name it. The majority of them have an available status one can set so that people might be able to glance at it quickly and see whether or not you're actually online or away from the computer. Hangouts is one of these that has the status message available and the Google+ version as well as the Chrome version of the app have gotten a change, which allows for any individual to update their status with a little more than an indicator that you're "online."
If you use Hangouts in either of these two formats, you can now set your status(whether it's online, away or busy)with emojis and a blip of text content that can expand things a little, just in case the act of being online or busy wasn't conveying things well enough to others. All told this feature is probably going to be seen with mixed reviews, as some likely don't care to elaborate on their online status with any more detail. However, if you're frequently using Hangouts but aren't always readily available to chat this could be a great addition to the service so you aren't getting blown up with messages every five seconds. This isn't a new feature of messaging services really, or other things like online games(League of Legends for example has always had a way for you to set your online status and then accompany that with a short message)but it is new to Hangouts and it might be fun to see what all the people we chat with type up to let us know what they're doing or whether they can or can't talk.
The update is live so you may already see it, but as with all things like this it could take a day or two, or three, to roll out to everyone that uses the Hangouts service. If you're eager to use it and are looking forward to inserting emojis of the food you eat with your status, give it some time and things should show up soon if they haven't already. On that note, it's time to try this out.