Way back in 2006, Twitter launched as Twttr on Twttr.com because it was SMS-based texting service, at first.
After then-CEO Jack Dorsey and his chairman Ev Williams realised the service should focus more on the Web, they went out and bought Twitter.com for $7,500.
Ev tweeted about the price last night.
Now, Twitter is worth more than a billion dollars.
These pages now hang framed in Twitter's offices. Cofounder Jack Dorsey told the L.A. Times he drew them up around 2000 or 2001.
'It was crystallizing the thought: What if you have LiveJournal, but you just make it more live? You have these people watching your journal, but it all happens in real time, and you can update it from anywhere. That document was an exploration of that concept.'
Reviewing Twitter for the first time in July 2006, TechCrunch founder Michael Arrington gave the service 'a thumbs up for innovation and good execution on a simple but viral idea.'
Commenter Justin doesn't look so precient in retrospect, having written, 'I think this is the dumbest thing ever! Who would want all their personal text messages on a public website for anyone to read and track?'
When a small earthquake shook San Francisco in August 2006 and word quickly spread through Twitter, it was an early 'ah-ha!' moment for users and company-watchers.
It might have been the first time people realised Twitter might be good for something more than saying what kind of sandwich was for lunch.
Twitter was built for old-fashioned SMS, but because the service is all about link and photo-sharing, it works best on tiny, mobile computer. Apple put 50 million of those on the market starting in January 2007.
Twitter hasn't updated its design much at all since Fall 2006. Instead, it lets third-parties developers build new and better ways for users to interact. One of those developers is The Iconfactory, which first launched its popular and award-winning Twitter app Twitterrific in January 2007. Today, dozens of companies make dozens of Twitter apps, for computers, set-top boxes, phones, etc.
Twitter launched as a product of another company, Odeo. But Odeo's founders saw its potential and bought out their own investors before launching Twitter as its own company.
That meant Twitter needing funding.
It got some from A-listers starting in July 2007 when Union Square Ventures, Charles River Ventures, Marc Andreessen, Dick Costolo, Ron Conway, and Naval Ravikant invested $5 million.
Correction: An earlier version of this post said Twitter raised $1 million. It raised $5 million.
Twitter users got to know the Twitter Fail Whale very well during Spring 2008, as Twitter surged with popularity and neearly caved under the pressure.
The whale still comes to visit sometimes, but not as often since Twitter quit handling messages with a Ruby server and switched to software written in Scala.
Prominant venture capitalist Bijan Sabet of Spark Capital joined new and old investors in writing Twitter a $22 million check in May 2008. Early rumours pegged the valuation at $80 million.
During the 2008 Presidential election, Twitter's profile rose with Barack Obama's. That candidate and others made it a central part of their grassroots efforts.
Shaq wasn't the first celebrity to join Twitter when he signed up in November 2008. But he's been the best.
His joining was beginning of transformation of Twitter from a geek service to something bigger and more mainstream.
The old line is that something's worth what someone is willing to pay for it. In Fall 2008, Facebook offered $100 million in cash and $400 million in stock to acquire Twitter. Twitter turned the offer down.
Following the Facebook offer, VCs beat down Twitter's door in February 2009 to hand it another $35 million, this time at a $250 million valuation.
In April 2009, CNN found itself in a high-profile race to one million Twitter followers with C-list celebrity Ashton Kutcher.
CNN eventually lost, but it only had a chance because it opened its wallet and bought Twitter account @CNNbrk from a user who had hooked the account up to CNN's RSS feed months before.
The story demonstrates how quickly Twitter went from being a service mainstream media ignored to one it couldn't live without in Spring 2009.
'The Oprah Effect' came to Twitter in April 2009. The traffic followed in a huge way.
When rioters protesting Iran's elections took to Twitter to get their message out and organise for several weeks in June, the service became nightly international news. The hype hasn't slowed since.