Investors have not looked kindly on a significant change at Facebook.
Shares in the social-media giant were off 4.16 percent in the first hour of trading, down US$7.80 to US$179.98.
By the end of the day, they had tumbled US$8.40, which was a 4.47 percent drop.
This came after Facebook CEO Mark Zuckerberg announced that users would "see less public content like posts from businesses, brands, and media" in their news feeds.
That's because it's crowding out content being shared by people's Facebook friends.
"We built Facebook to help people stay connected and bring us closer together with the people that matter to us," Zuckerberg said on his Facebook page. "That's why we've always put friends and family at the core of the experience. Research shows that strengthening our relationships improves our well-being and happiness."
He acknowledged that these changes will likely result in some measures of user engagement going down. But this would be offset by the experience being "more valuable".
"At its best, Facebook has always been about personal connections," he stated. "By focusing on bringing people closer together—whether it's with family and friends, or around important moments in the world—we can help make sure that Facebook is time well spent."
Meanwhile, City University of New York journalism professor Jeff Jarvis has written a skeptical post about the change.
He declared that he hopes Facebook doesn't "use this change to exploit media companies for more advertising revenue when the goal is to inform the public".
"I wish that Facebook would not just connect us with the people we know and agree with — our social filter bubbles — but also would devote effort to making strangers less strange, to robbing the demagogues and hate mongers of their favorite weapon: the Other," Jarvis added. "That, I firmly believe, is the most valuable thing Facebook could do to combat polarization in our world: creating safe spaces where people can share their lives and perspectives with others, helping to build bridges among communities."