So lets star by going back to where Instagram started and now how its evolving.
Instagram launched in 2010, giving users a platform to share images, and has evolved significantly over the years. Its original version was chronological. If a user followed 1,000 other users, all of the posts created by those 1,000 people would appear in their feed in the order that they were posted – from the most recent to the oldest. With this model, the user had the option to easily access all of the posts from other users that they followed.
No longer is this the case. Last summer, Instagram started rolling out its new algorithm, and said in an announcement: “To improve your experience, your feed will soon be ordered to show the moments we believe you will care about the most. The order of photos and videos in your feed will be based on the likelihood you’ll be interested in the content, your relationship with the person posting and the timeliness of the post.”
Basically, if people who follow aren't liking and commenting actively on your post often, its harder for them to see the posts as they go live.
Im not sure if you have noticed in the last 2 weeks but engagement levels across the board have begun to decline. You may notice less interaction and activity on the posts due to this - please don't stress we aware of the changes and even though Instagram is yet to release what final changes are, and how we benefit from them, rumour has it that Instagram is increasing its targeting capabilities, making it even better for brands to be online.
Here are some interesting reads to learn more about the changes: