Facebook's News Feed: What Changed and Why

As Winston Churchill once said, “to improve is to change; to be perfect is to change often." It's a maxim Facebook seems to have adopted wholeheartedly when it comes to the News Feed.
Posts appearing in your news feed today likely look different from the posts you saw six months ago, both in appearance and content. The simple reason for this is Facebook is learning more about you, and that means the company's news feed algorithm is better at determining what you like and what you dislike.

The average Facebook user has roughly 1,500 stories per day that could appear in their news feed. Facebook surfaces about 20% of those stories. That's where the algorithm comes in, and that's why Facebook is constantly tweaking it.
The social network has been particularly busy with the News Feed the past six months, releasing a number of algorithm updates and a significant redesign. It's all part of CEO Mark Zuckerberg's ultimate goal for the product: to provide every user with a perfectly personalized digital newspaper.
What exactly has changed in the News Feed algorithm in recent months, and why? Here's everything you need to know.
What You're Seeing More Of:
Auto-play Videos (Including Ads)
Facebook first tested auto-play videos in the mobile News Feed in September. Facebook's web version got auto-play videos in December. The company began testing auto-play video ads a week later, but postponed full implementation. In March, Facebook announced auto-play video ads would begin to roll out to all users over the "next few months."
That means some of you know the ads all too well. But if you're thinking "auto-play ads? Never seen one", then rest assured, you will.
These videos play automatically as you scroll through your News Feed. They won't have any sound unless a user clicks on them. This does not include shared videos from third party sites, like YouTube, but only videos uploaded directly to Facebook.