As you begin to add other people to your circles on Google Plus, your stream on your Home page will naturally begin to fill with posts and updates which you will most likely want to interact with, comment on and react to. You might just want to reply to someone who has left a comment on one of your own posts for example or take part in an on-going discussion about a subject that you are interested in. As you scroll down your stream to read all of the posts and decide to join in a topic of conversation, you have quite a few choices at your disposal regarding how to react either to someone else’s post or comment or to add your own reply or comment to that particular post.