The new feature can be found in the bottom left-hand corner of your Google+ profile and is meant to mimic the Twitter direct message feature which allows Twitter members to send messages to people who are following them.
As Google explains the new product:
Google Chat makes it easy to chat with people you have relationships with. In Google+, you can chat with anyone in your Circles who also has added you to their Circles. And, when you’re not using Google Plus, you’ll still be able to chat with them using Google products including, Gmail, the Google Talk client, iGoogle, Orkut and 3rd party apps. [Read more…]