Of course, Snapchat is not most other social media companies — and has already had a camera home screen for many years. News outlets pointed out that Facebook's Halloween "masks" looked pretty similar to Snapchat's lenses and filters.
"Look, they're trying to chase Snapchat," Richard Greenfield, BTIG media and technology analyst, told CNBC's "Fast Money: Halftime Report" on Thursday. "So you're pivoting technologically, and I think you're doing that because you see what's happening in terms of the Snapchat engagement. .... The question is, 'Can you monetize it the way Facebook's monetized historically?' And that's going to be a real challenge for the company to keep up this level of growth."
They may look similar, but the two companies stack up differently in key areas such as users, infrastructure and advertising demand.
Instagram's "Stories" product, Facebook's answer to Snapchat's ephemeral photos, has more than 100 million daily active users, Zuckerberg said on Wednesday. That means since Instagram launched the service in August, it's crept up on the 150 million daily users that Snapchat said it had earlier this year.
To be sure, Snapchat, which is privately held, doesn't release user numbers on a quarterly basis, so it's hard to know how much Snapchat has grown in the same period. But Facebook's properties as a whole certainly have massive scale, with 1.18 billion daily active users as of the September quarter, up from 1.13 billion in July.
That means that Facebook, as a whole, added about 50 million daily users in the quarter — about a third of Snapchat's entire user base, as last reported.
It's important to note, however, that, quality and quantity of users both matter.
Research varies on whether Facebook or Snapchat is more popular among teens and millennials, key demographics for marketers.
Facebook and Snapchat have an equal share of mobile app user share in the 10 to 15 age group, according to Newzoo research cited by eMarketer. But Snapchat takes share among users 16 to 30, according to that data.
Piper Jaffray analyst Gene Munster estimates that Facebook engagement is decreasing among teens, according to a survey of 10,000 teens. But Instagram and Snapchat are growing in conjunction, he estimates. Still, Cowen's proprietary data shows that in the 18 to 24 cohort, Facebook has more users than Snapchat, analyst John Blackledge told CNBC's "Squawk Alley" prior to Facebook earnings.
The pair also operates in different markets. In the U.S. and Canada, Facebook said it had 178 million daily active users in the quarter, where Snapchat said it has more than 60 million. On any given day, Snapchat reaches 41 percent of all 18 to 34 year-olds in the U.S., according to Nielsen research commissioned by Snapchat.
Facebook's gargantuan scale means the company will have to invest aggressively in data centers to serve quick, quality video to all its users.
"In the actual delivery of video side, it's just much more intensive technically," Zuckerberg told investors on a conference call on Wednesday. "There aren't that many companies that can do this at the scale that we're talking about, and this has been a big advantage for us. In rolling out things like Live, we've had this infrastructure that we've been building out for a decade all around the world, and that allowed us to build a product like Live where someone has to stream something live from their phone to potentially hundreds of thousands of people around the world. From a phone, that's a difficult scaling problem."
Luckily, as the number two global digital ad publisher, according to eMarketer, Facebook has the funding to make those kinds of investments. The company had about $6 billion in cash and equivalents as of the latest quarter.
It's hard to know what kind of cash and infrastructure Snap — Snapchat's parent — has access to.
A 2014 Wired report estimated that by storing less data, and using Google's Cloud, Snapchat is much cheaper to run than competitors. As far as cash, Snap's received an estimated $2.6 billion in funding, according to CB Insights.
Talent is another major input into successful video, as both Snapchat and Facebook battle for the most influential celebrities on their platform. That opens the question of whether paying talent is sustainable, Greenfield said.
"As we saw with Vine, if you don't pay the talent, they ultimately go someplace else," Greenfield said. "I think talent is very frustrated with Facebook not paying them ... they're starting to pay certain people little bits of money."
Earlier this year, eMarketer research estimated that Snapchat's ad revenue will grow to $935.46 million next year, a 2 percent stake of total social network ad spend. By comparison, Facebook's ad revenue was $6.8 billion just during the latest quarter alone, and the company earned nearly $17.9 billion in the 2015 fiscal year, mostly from ads.
However, it's important to note that if Snapchat closes in on $1 billion ad revenue next year, that would be close to triple the eMarketer estimate for this year's sales, a super-fast growth rate, even for social media. Facebook, on the other hand, has warned investors that it may see ad revenue growth slow.
Still, while Snapchat has recently opened its advertising business more, Facebook is still a must-have for marketing, Adam Berke, president of AdRoll, said in a statement.
"As marketers look for opportunities to allocate incremental budget, it's easiest to turn the knob up through advanced buying tools versus trying to figure out a whole new system or one that is still very new, like Snapchat or Pinterest," Berke said.