This week in social media, Facebook continued encroaching on YouTube's turf, Twitter continued rolling out changes that mirror Facebook, Pinterest officially launched advertising, and Snapchat raised nearly half a billion in funding from an eager investment round.

It's time for Social Media Saturday!

Facebook:

Expanding its Video Offerings with Pages

Facebook has set YouTube dead center in its sights already by expanding its in-network video offering, luring viral video hits to stay within its fold by encouraging users to upload videos there with promises of more exposure.

Now, according to The Motly Fool, Facebook is about to do the same for small business: It's testing out a new design for Pages, adding more prominence to videos and mirroring YouTube's "Channel" page outline.

Facebook's "Pages" is a way for businesses to create unique Facebook venues for brands and network with potential customers and publicize their offerings to a wider audience. The new "Pages" will do the same but will likely encourage businesses to feature a video at the top of the page, with playlists for their audience stacked below.

This all comes back to Facebook in ad revenue, for which the social network is still testing formatting and pricing options. With digital video only expected to expand online over the coming years, Facebook is just starting to go after a big piece of YouTube's pie.

Zuckerberg Crowdsources His New Year's Resolution

... using Facebook, of course. Facebook CEO Mark Zuckerberg is known for challenging himself to do one thing different in his daily life each year -- from (famously) learning Chinese to simply trying to meet someone new every day -- but this week, Zuckerberg asked Facebookers to help him come up with 2015's goal for the first time.

This new addition to Zuckerberg's New Year's tradition is in line with his already-clear professional intention to open the company up to the Facebook userbase. Zuckerberg recently instituted a weekly Thursday Q&A on Facebook between staff (including himself) and Facebookers.

"At our last town hall Q&A, someone asked me what my challenge will be for the new year and I said I'd love ideas from our community. I have an idea of what my next challenge might be, but I'm open to more ideas before the new year officially begins," wrote Zuckerberg on his Facebook page.

Bring on the flood of suggestions, including some hilariously snarky ones -- like "delete Messenger," "delete users who send Candy Crush invites" and "finish college" -- which Mashable has rounded up here.

No word from Zuckerberg yet if he's decided on an idea offered up from his constituency, but PCMag noted that one suggestion, "pay off a person's student loan everyday. Or one person a week," would be a pretty doable for the 30-year-old billionaire.

Twitter:

More Like Facebook, Again

That Twitter has struggled with negative investment perceptions since its IPO is not a secret; neither is Twitter's strategy to allay Wall Street's fears -- namely, to add more features that it thinks made Facebook a success.

So the official Twitter "while you were away" email you might find in your inbox shouldn't be a surprise either. It's the latest salvo in Twitter's frantic Facebookization, a feature presenting a recap of Twitter timeline activity that you might have missed since the last time you used the Twitter app or logged into the website.

Twitter began rolling out the new feature earlier this week, which pins tweets that Twitter determines are the most engaging to prominence at the top of your timeline.

"While you were away," according to the Guardian, represents the second official feature that moves away from Twitter's traditional chronologically ordered timeline, after Twitter's advertising initiative, "promoted tweets."

It's part of Twitter's new "Timeline Highlights" strategy to unearth content most likely to keep you actively using their app (and also more likely to attract those all-important new users), so Twitter purists, expect more irritation to come.

Pinterest Launches Ads

When the big ball dropped, Pinterest officially began a new era. Starting this week, Pinterest officially is open to marketers interested in creating "Promoted Pins" across the image-heavy social media sharing site.

Pinterest has already been experimenting with the advertising system, of course, and the company has finally decided on pricing, features, and options. According to The Next Web, promoted pins will look just like other pins, and will similarly be savable, pinnable and appear in search results of Pinterest users. But marketers will only have to pay for the clicks their pins actually generate.

Snapchat Gets Richer

This week Snapchat found a particularly nice way to ring in the New Year, by sealing up a round of investment (leaked in an SEC filing that TechCrunch found) worth almost $500 million.

And according to TechCrunch's sources, the company that Zuckerberg couldn't buy for $3 billion a little over a year ago is now valued at around $10 billion. Happy New Year indeed, Snapchat.