Instagram has replaced its existing news feed with a algorithmic newsfeed meant to show you the most relevant posts. The previous feed was reverse chronological, showing you the latest images first and then going back in time as you scroll down. Now you see images that are meant to be more relevant to your interests. As you scroll it shows in decreasing order of relevancy. Unfortunately not many are happy with this change.
To many the new feed is less interesting than seeing it based on post times. The more popular accounts will now have more prominence. Multiple posts from the same user will get shown right at the top even though those posts were not from the same time frame. Some users also complain of a lack of time sensitive relevancy, such images taken from live concerts appearing at the bottom. It also forces users to keep scrolling down to see if they missed anything since the post at the top is no longer the newest.
Instagram insists that this change will bring about an improvement in the experience for its users. The service has been criticized for switching to this feed in order to improve the experience for advertisers and increase revenue. It remains to be seen if the new feed is an improvement over the old or if they will switch back.