Facebook is 20 years old today.
On 4 February 2004 Mark Zuckerberg launched 'thefacebook.com' from his Harvard dormitory.
Two decades later, many users struggle to remember a time they weren't scrolling through its news feed - or that of its social media sibling, Instagram.
While allowing us to find long-lost friends and family, and supporting small businesses, its 20-year history has been chequered with controversy - from the Cambridge Analytica scandal and allegations of election interference, to lacking protections against harmful content.
Here we look back at the last 20 years - and what could be in store for the trillion-dollar tech company, reports Sky News.
2004
When computer science and psychology student Mark Zuckerberg launched thefacebook.com, it was only for students like him - and not open to the wider public.
It was designed so they could exchange posts, messages, and create a network of 'friends'.
Its mainstay was the 'wall', where users could publish posts or write on others.
Facebook was hot on the heels of its early 2000s rival MySpace and was not monetised so refreshingly free of advertising.
But just a few days after it launched, three of Zuckerberg's fellow Harvard students accused him of stealing their idea for a similar social network they had created called ConnectU. Twins Tyler and Cameron Winklevoss and Divya Narendra claimed Zuckerberg had helped them with ConnectU, but eventually agreed to settle their legal case in 2008 - in exchange for $65m (£51m), including Facebook shares, and their ConnectU business.
By the end of the year, Facebook already had a million users.
2005
You couldn't upload photos on Facebook until 2005, when the ability to sub-categorise pictures into albums provided the first platform for the 'photo dump'.
The inclusion of photos on Facebook also gave birth to the concept of the 'profile picture'.
The year after the launch, Zuckerberg also decided to drop the 'the' and bought the domain name Facebook.com for $200,000 (£170,000) from a company called AboutFace Corporation.
2006
A year before the first iPhone was released, Facebook launched a bespoke mobile site for the first generation of smartphone users.
On 26 September 2006 Facebook expanded beyond university students for the first time - allowing anyone with an email address over the age of 18 to join.
With the expansion came the news feed, giving users a curated selection of their friends' posts, and the wider world the concept of 'scrolling'.
2006 was also the first year Facebook faced major controversy. Zuckerberg was forced to apologise after his Beacon feature, which sent data to third parties to create targeted ads, began showing users' purchasing history on their profiles without their consent. Eventually people could opt to turn the feature off.
2007
Facebook's fourth year brought with it several firsts - videos, ads, Marketplace and pages.
Introducing advertising created huge revenue streams and gave businesses a new way of selling themselves online.
Pages also meant companies and other organisations could create mini-professional profiles that were distinct from personal ones.
On a smaller consumer scale, individual users could advertise goods for sale.
2008
Facebook launched its own instant messenger 'chat' in March 2008, which became a separate app entirely known as 'messenger' in 2011.
With the iPhone came a dedicated Facebook app, separate from its mobile site.
A second major data breach saw the dates of birth of more than 80 million users published on the platform.
2009
This was the year of the 'like' button.
And to rival Twitter, which had launched in 2006, Facebook also introduced tagging for photos, posts, and comments.
2010
January 2010 saw Facebook's first purpose-built data centre open in Oregon.
By the middle of the year the site had reached 500 million users, with 'groups' also added for the first time.
In October, The Social Network film was released. Starring Jesse Eisenberg as Zuckerberg, it set out to tell the story of Facebook's beginnings and the subsequent battle between its founder and the Winklevoss twins. Although it was a huge success in Hollywood, Zuckerberg criticised parts of it for being inaccurate.
2011
In 2011, Facebook began its long and complex relationship with law enforcement.
The US Federal Trade Commission (FTC) sued it for multiple breaches of its privacy policy. These included users' friends list being public even when they had made them private, and non-consensual sharing of their personal data with advertising companies.
By 2023, the FTC was on its third case against Facebook.
2011 was also the year the much-loved Facebook wall was replaced with a timeline.
2012
In April 2012, Facebook bought Instagram for $1bn (£0.8bn) and in May it was floated on the stock market for the first time.
Zuckerberg said he bought the photo-sharing app because it was a "threat" to Facebook's future and the IPO was one of the biggest and most anticipated in history, with an estimated share value of $104bn (£82.2bn).
Oculus, a Facebook-owned brand, also produced its first virtual reality headset.
Later that year the platform reached a new milestone of one billion users - a seventh of the world's population.
2013
In June 2013 a bug saw the email addresses and phone numbers of six million Facebook users accessible online.
It was thought to have been an issue since the year before but was only spotted in 2013.
In terms of features, this year saw users able to edit their posts retrospectively and share stickers as well as emojis.
2014
Two years after the acquisition of Instagram, Facebook bought WhatsApp for 19 times the amount. WhatsApp was created in 2009 for iPhone by a former Yahoo employee.
Today more than half of the world's internet users have WhatsApp.
2015
At the very end of 2015 the Cambridge Analytica scandal was first reported by The Guardian and The New York Times.
Over the next few years it emerged that the UK-based political consultancy firm had harvested millions of Facebook users' data for various clients without their consent.
The scandal implicated US politicians, and the Vote Leave campaign, among others. Eventually the UK Information Commissioner ruled the firm was not involved in the Brexit referendum beyond "some initial enquiries… in the early stages" by UKIP.
It was hugely damaging for Facebook's reputation and its finances.
2016
As self-shooting live broadcasts became more and more of a feature on the internet, Facebook Live was launched.
Three years later it was used by terrorist Brenton Tarrant as he carried out the Christchurch Mosque shootings in New Zealand, which killed 51 people and left 40 injured.
AI now exists to help Facebook identify and block people from filming themselves carrying out atrocities.
2017
A year after stories became a feature on Instagram, Zuckerberg and his developers introduced them on Facebook.
In a less popular move, Facebook 360 was launched to enable users to upload panoramic photos to their profiles.
2018
The Cambridge Analytica scandal came to a head in 2018, with a raid of their London offices and the company eventually disbanding.
It led to Zuckerberg being compelled to appear before US Congress to answer questions for the first time.
Facebook also suffered the fallout of another data breach that year in which hackers accessed logins of 50 million users.
And former deputy prime minister Nick Clegg joined the company as vice president of global affairs. He has since been promoted to president.
2019
Three separate data breaches continued to chip away at Facebook's image in 2019.
The first saw 540 million users' data made public, the second happened when Facebook "unintentionally" released emails of more than 1.5 million people, and the third saw the names, phone numbers and usernames of 267 million people made public.
In response to privacy concerns, Meta says it's since invested $5.5bn (£4.3bn) to tackle the issue, with a team of 3,000 people worldwide.
"As expectations around privacy evolve, it's critical for companies to continue investing in guardrails and processes to meet people's privacy needs and expectations," it said in a recent statement.
2020
A second FTC case against Facebook resulted in a court order banning it from monetising data acquired from profiles of users under 18 and limiting its use of AI.
This year, as part of its response to the Cambridge Analytica scandal, Facebook agreed to "fundamentally shift our approach to protecting people's privacy" and paid a $5bn (£3.9bn) fine.
2021
As COVID continued to separate people all over the world from their loved ones, Zuckerberg announced Facebook Inc would become Meta.
Not only was Meta a parent company for Facebook, Instagram, WhatsApp and other assets, it also laid the groundwork for the 'Metaverse'.
In its launch announcement, Zuckerberg described it as "letting you share immersive experiences with other people even when you can't be together - and do things together you couldn't do in the physical world" and the "next evolution in a long line of social technologies".
In December 2021 a joint $150m (£118m) lawsuit sued Facebook over allegations it failed to address misinformation that promoted the genocide of Rohingya Muslims in Myanmar.
In response, Meta created a Myanmar-specific policy to remove praise, support, and advocacy of violence by Myanmar security forces and protesters on all its platforms. It has also banned the Myanmar military itself, including any pages, groups, and accounts representing military-controlled businesses.
Its latest statement added: "Our team continues to monitor the situation on the ground in Myanmar and we will continue to take any action necessary to keep our community safe."
2022
Meta's safeguarding measures against harmful content came under unprecedented scrutiny in 2022 when a UK coroner ruled that "negative online content" had played a role in someone's suicide for the first time.
The case was that of Molly Russell, a 14-year-old schoolgirl from London, who was found dead in her bedroom in 2017.
Her father Ian campaigned against under-regulated tech companies after evidence emerged she had viewed content that promoted self-harm and suicide on platforms such as Instagram and Pinterest.
The firm's head of health and wellbeing, Elizabeth Lagone, attended the hearing in person and said many posts viewed by Molly would have violated Instagram's policies, for which she apologised.
2023
By 2023 the Metaverse had begun to cost its parent company dearly.
By the end of the year, Meta Reality Labs had haemorrhaged $46.5bn (£36bn). As such, 2023 quickly became Zuckerberg's self-proclaimed "year of efficiency" with 21,000 planned job cuts.
Meanwhile, Meta honed in on its rival X, formerly Twitter, which had not long been bought outright by Elon Musk. To do so it launched its own subscription service - Meta verified - and a separate X-style app for Instagram called Threads.
By the end of the year, Meta was also facing its third privacy case from the FTC in the US.
Bd-pratidin English/Lutful Hoque
