On Instagram, Zuckerberg shared snippets of his early days at Facebook.
"Twenty years ago, I launched a thing. Along the way, lots of amazing people joined and we built some more awesome things. We're still at it and the best is yet to come," Zuckerberg posted on Instagram, sharing a reel which included his old Facebook display picture.
The official Instagram handle of Facebook commented: "Love you dad."
In less than a year of its launch, Facebook had one million users, and within four years it had overtaken its rival MySpace.
By 2012, Facebook had surpassed one billion users a month.
At the end of 2023, Facebook reported it had 2.11 billion daily users.
Meta's family of apps, which includes Facebook, Instagram, Messenger and WhatsApp, are now being used by 3.19 billion people daily in the fourth quarter, up from the 3.14 billion.
The Family monthly active people figure was 3.98 billion as of December 31, 2023, an increase of six per cent year-over-year.
Meta CEO Mark Zuckerberg is now the fifth richest person in the world following a surge in Meta's share price.
Facebook's parent company Meta is now an advertising giant.
Meta last week reported more than $40 billion in revenue for the last quarter of 2023 and around $14 billion in profit.
However, Facebook also faced billions of dollars in fine in the past over its poor data collection practices.
In the Cambridge Analytica scandal in 2014, Facebook paid $725 million to settle legal action due to a significant data breach.
In 2022, Facebook also paid a 265 million euros fine for allowing personal data to be extracted from the site.
Last year, the social network was fined a record 1.2 billion euros by the Irish Data Protection Commission, for transferring European users' data outside of the jurisdiction.
Facebook is currently appealing against the fine, reports the BBC.
Instagram Threads has now reached 130 million monthly active users, up 30 million from the last quarter.
Zuckerberg said during the company's fourth-quarter earnings call that Threads is "growing steadily".
Threads had a record-breaking launch, reaching 100 million registered users within its first five days last July. But the interest faded over time.
