In a blog post, the company explained:

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. As we begin, we’re focusing on optimizing the order — all the posts will still be there, just in a different order.

Not surprisingly, Instagram’s reaction was met with fierce criticism from users who say they’re happy with chronologically-ordered feeds. As of Thursday, a petition urging Instagram to reverse its decision had received nearly 86,000 signatures on, and Twitter was filled with comments from nonplussed Instagram users.

The impact on influencer marketing

Users may not be the only ones who aren’t thrilled with the change Instagram will be making. Instagram has become one of the most prolific social channels for brand marketers, and is a particularly prolific channel for influencer marketing. Many fashion brands, for example, are investing heavily in reaching consumers through popular Instagram users.

While Instagram says that ”people miss on average 70 percent of their feeds,” the application of an algorithm to user feeds adds a level of uncertainty that could be uncomfortable for brands paying influencers to promote their wares. After all, the algorithm could either increase or decrease reach.

This will naturally be totally out of the control of brands, which will now have to contend with trying to understand how the algorithm works and what they can do to optimize their influencer marketing efforts in light of it.

It isn’t personal, it’s business

Of course, Instagram says that it’s changing the way feeds work to help users discover the content that’s most relevant to them, but the reality is that Instagram’s burgenoning ad business stands to benefit the most.

With the greater ability to control reach, Instagram can more easily pitch brands on its ad products. Brands will find such a pitch familiar: with organic reach on Facebook constrained by EdgeRank, many turn to Facebook ads to distribute their messages on the world’s largest social network.

For better or worse, brands need to accept that algorithms will ultimately dominate just about every digital channel, and social is no exception. Twitter and Instagram are just the latest popular social platforms to bring an algorithm to services where many users don’t want them, and they certainly won’t be the last.