This week in social media, Facebook unveiled its latest push into online video, seeking to rob top rival YouTube of views. Meanwhile, Twitter went through some major company changes under new CEO Jack Dorsey and a new study surprised no one by revealing that teens prefer Instagram, with Snapchat right behind, over other social networks.

It's time for Social Media Sunday!

Facebook

The Plan to Annex More Video from YouTube

On Wednesday, Facebook announced a several-part plan of attack against the dominant online video site YouTube, though its newsroom post was titled more innocuously "Testing New Video Experiences."

In it, Facebook detailed several initiatives in online video, including rolling out those 360-degree videos we reported on earlier in September, testing a "Suggested Videos" feature, experimenting with a dedicated location on its platform for only Facebook videos, and working on a new feature for its iPhone app (and later for Android and the web) that would float playing videos on the screen as users scroll through their News Feeds.

"Since our update last year, video has continued to grow on Facebook," wrote VP of product management Will Cathcart in the company's announcement. "It has become an integral part of how people around the world discover, watch and share videos they care about every day."

Over the past year, Facebook has been trying to offer better video sharing features in its own platform, which not-coincidentally helps the company phase out its reliance on users embedding YouTube videos on the site.

But with better viewing options, "Suggested Videos" built with the company's incredible trove of user data, and, especially, a dedicated page for Facebook videos only, Facebook may do more than phase out YouTube from its own territory. It could start eating into a big piece of YouTube's massive trove of creators, viewers, and ad revenue.

Twitter

Big Changes Under Dorsey

This week was a tumultuous one for Twitter, but not for the usual reasons. Rather than getting hit by Wall Street or suffering internal bickering, it was some bold changes instated by Twitter co-founder and recently installed CEO Jack Dorsey.

Early in the week, Dorsey announced layoffs for over 300 people at the company, which amounts to about eight percent of its total workforce, according to Re/code. "Product and Engineering are going to make the most significant structural changes to reflect our plan ahead," wrote CEO Jack Dorsey, announcing the layoffs on Tuesday morning. "We feel strongly that Engineering will move much faster with a smaller and nimbler team, while remaining the biggest percentage of our workforce. And the rest of the organization will be streamlined in parallel."

The next day, Twitter announced it had snagged Omid Kordestani, a veteran chief business officer for Google, appointing him as the new chairman of Twitter's board of directors. According to Re/code, Google wasn't too hurt by the move, saying, "We're excited for Omid and very happy for Twitter. Omid was instrumental in establishing Google's business and helped us develop really close, longstanding partnerships across the industry. We wish him every success in the years ahead."

Kordestani replaces former CEO Dick Costolo, who had stepped down from his CEO position at Twitter earlier this summer and then subsequently vacated his board position a week before Dorsey took permanent control.

If that wasn't enough shifting around at the core of Twitter this week, on Friday former Microsoft CEO and bombastic Clippers owner Steve Ballmer confirmed he had recently bought 4 percent of Twitter. Ballmer told Bloomberg he was happy with Dorsey for making Twitter "leaner, more focused," in the past few months.

Instagram

Teens' Top Choice in Social Networking - Study

Finally this week, Piper Jaffray released a survey of 9,400 teens that confirmed something most people knew: Teens use Facebook and Twitter, but most prefer Instagram as their top choice, with Snapchat following closely behind.

According to the Wall Street Journal, the study found that one-third of the teens surveyed said Instagram was their most important social network. Twitter received 20 percent of responses with Snapchat behind by only one percentage point, and Facebook received only 15 percent of teens' top choice, falling behind into fourth.

Facebook doesn't have much to worry about, of course, since it bought Instagram in 2012, but it does show further evidence of what might be called Facebook's "parent effect": Due to the popularity of Facebook across demographics, including Boomers and even older adults, teens find Facebook to be a less attractive option for expressing themselves online.