Twitter has always been a “show it all” kind of social network. But all things must change. For some time, there have been rumors about a new algorithm appearing, and it looks like the rumors have come true. The microblogging network has released its new toy.

Though the new algorithm has rolled out, it is not automatically applied to accounts. For the time being, at least on in desktop mode, must opt in through their settings to have the algorithm applied.

But what is the algorithm? Twitter is now putting a “what you missed while you were away” feature on the timeline. Many of us have seen this for a while on the mobile app. That was a test phase. The roll-out on mobile and desktop has started, and it is likely to be automatically implemented on everyone’s timeline at some point. The “while you were away” feature puts top tweets from the people you follow in a stream so you can catch up with what you missed. Regardless whether you’ve been away 10 days, 10 minutes or 10 seconds, the section will still populate the top “missed” tweets.

The reverse chronological timeline remains the order of the day, meaning the most recent tweet is shown first, but now all of that comes after the “what you missed” section. Twitter said the new feature is an attempt to show users more of what they want to see, as opposed to requiring users to scroll through a bunch of stuff that may no longer be relevant. The company also trying to show users content from people users find the most valuable—the people you most engage with.

That doesn’t sound so bad, except users now might miss more tweets from people Twitter doesn’t consider “important,” because the “away” tweets will take attention from the most current tweets. At least, this is the concern. We will see how it affects the lifespan of tweets, which currently only last about 18 minutes.

The changes emphasize the importance of engagement. If you want people to see your tweets, it is even more important that you engage with your followers and they engage with you. If they engage with you, then you have a higher chance of showing up in their “while you were away” timeline. If you don’t, then your tweets will be buried in the chronological timeline.

The algorithm is simple: Engage and you might appear in the “while you were away” section of your followers’ timelines; don’t engage and you definitely won’t.

Lauren MacEwen is the primary strategist and CEO of 7 Veils Media.