Whatever you think of Facebook, its growth has been phenomenal - from a few Harvard students in the early 2000s to almost two billion people.
Once upon a time, broadcasting your "likes" to all and sundry was a thing. Remember that? What about poking?
Oh, and remember that time there was a social engineering experiment into emotional contagion?
The evolution of Facebook has seen the platform transform from a fancy intranet in the early 2000s to the largest social network in the world, used by an inconceivable number of people.
Something like 1.86 billion people use Facebook. The world population is an estimated 7.5 billion.
It was meant to connect people - and it does - but its sheer size and seemingly exponential growth into a company with accounts, shareholders, a profit margin and a global reach worth billions of dollars has raised many questions about power, privacy, and accountability.
Since its birth, Facebook has struck privacy issues while, paradoxically, people in their millions continue to submit personal information.
A few years ago, some of Mark Zuckerberg's early instant messages were leaked online. He'd referred to early adopters of "The Facebook" as "dumb f...s" for trusting their information to a third party.
In an interview with The New Yorker, Uncle Zuck described the comments as regrettable and said he had matured.
At one point, the site told friends things you bought. In the US, the Federal Trade Commission, the US government's consumer rights' arm, was less than happy and the service agreement was changed.
Facebook's short, world-changing history, and its relationship to privacy, is probably best described as a moveable feast.
In 13 years, the privacy settings have morphed away from the classic meaning of private as "not public", or "for one's use", into multi-level menu settings and sub-settings, data harvesting terms and conditions, and information gathering algorithmic processes that the company uses as the source for its multibillion dollar revenue.
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In 2006, default settings were tweaked and your name, profile photo, and school were public unless you changed the settings.
2007 was a watershed year, when mobile support started, a friends' list arrived, the news feed was launched, and anyone over 13 with an email could sign up.
Back then, the news feed displayed content from friends' feeds so you could see what they were doing. It faced criticism for being a bit, well, stalker-y.
The feed evolved into a real-time ticker and, by 2011, there was the "timeline" profile.
User numbers exploded in 2008 and 2009, jumping by 250 million people in a year. That's around the population of Indonesia in 12 months.
Its exponential growth curved ever upwards. By the end of '09, the site had 350m users.
In 2009 and 2010, users were upset about the amount of information available to others, particularly after it emerged advertisers were able to identify some information (although apparently advertisers were not identifying users by name).
A new privacy option applied to every post, giving users the ability to make certain photos or other content private. The old privacy "networks" were gone and Facebook introduced four control settings; friends; friends of friends; everyone; and customised.
Concerns mounted over privacy controls during the year, when the Canadian Privacy Commissioner reviewed policy and third-party access to users' information. Facebook changed tack to give people more permission options over third-party information sharing.
Users increasingly complained about the privacy settings being confusing or overwhelming.
One of the biggest privacy bloopers was the large-scale tweaking of users' feeds experimenting with people's emotions, revealed in 2014.
One way of getting your head around the site is to think of Facebook as a two-sided interface.
There's the public-facing side, the one you curate, post to, add photos, and scroll through. Then there's the engine room, the other side, the infrastructure, servers and data banks, programmers, people, marketing, and corporate philosophy.
At the same time, the network is an enormous advertising platform.
Marketers trade information with the big tech companies. Your date of birth, or phone number and addresses can be supplied to third-party marketing firms.
Third parties aren't meant to identify your name, or your Facebook account. They can identify things like your age, where you live, perhaps your job, and your latest purchase, and on that basis they target advertising to data-linked accounts.
A Facebook spokesperson says "certain data" is shared with advertisers so they know which ads work best.
"This information includes measurement statistics, such as the number of people who saw and/or clicked on an ad, but it doesn't include things [like] people's name or contact information, their date of birth, location, employer, or information about items you may have purchased on Facebook."
It begs the question: what does privacy really mean?
Privacy isn't private any more. Instead, in this context, "privacy" refers to allowing personal information to become publicly available, traded, and used as a commodity.
Facebook archives corporate announcements so it is possible to go back and look at the changes they introduced and trace the evolution of the network from 2006 - when it was referred to as a "social utility" - to its current version. But this is no easy task.
Overall, the site's privacy policies fell in ranking using an internationally accepted framework. The study suggested the site's privacy policies were increasingly opaque and difficult to understand.
In an emailed statement, a Facebook spokesperson said: "Privacy is core to everything we do. We work to keep people informed about privacy from the day they sign up for Facebook and beyond.
"People who use Facebook want control over what they share, so we build our products to give them exactly that.
"We're focused on helping people understand how to use the tools we've created so they can make informed decisions and control their experience."