Instagram has been pushing forward on their competition in the past year. The Facebook company has added features of Snapchat in stories and filters, and chat features of WhatsApp.
This time around Instagram is going to make it easy to see who is online and ready to chat. The people you follow will now feature a green dot on their profile image. Instant gratification of the possibility of a reply definitely makes it easier for users to engage.
Read more on the Instagram blog for their new feature.