Our story begins in San Francisco.

The duo decide to turn their loft into a lodging space with three airbeds on the floor, and promises of home-cooked breakfast in the morning.

They set up a simple website and got three renters (two guys, one girl) for $80 each. This was their first guest, Amol.

Brian and Joe call on their former roommate and “brilliant engineer”, Nathan Blecharczyk, to join the venture.

They coordinate the launch of the company, then called Airbed & Breakfast, around the Democratic National Convention. They wanted to take advantage of the hotel room shortage.

They buy a ton of cereal, design boxes for each of the presidential candidates, and get to work packaging.

Obama O’s and Cap’n McCains

The guys sell 500 boxes of each cereal for $40/box, ultimately raising $30k to put towards Airbed & Breakfast.

Still, not much traction. The guys start living off of leftover cereal.

[protected-iframe id="62338ba9a21b901dff0af32a15a237e2-24588526-23450179" info="http://pshared.5min.com/Scripts/PlayerSeed.js?sid=281&width=480&height=401&playList=518408449" style="text-align:center"]That last gif was misleading. It wasn’t even a bunch of different varieties of cereal. It was just a lot of one kind of cereal. They called it a real “low point”.

Convinced to hook up with Paul Graham at dinner one night, Airbed & Breakfast joins Y Combinator’s 2009 winter class pulling in an additional $20,000 in funding.

Airbed & Breakfast becomes Airbnb

The company lands a $600k seed round from Sequoia Capital and Y Ventures, and finally stops eating left-over cereal.

Fred Wilson, however, rejects the idea.

Realizing they’d need to take care of payments to scale, Airbnb introduces a booking fee, asking for a small percentage from the host and a slightly larger percentage from the booker.

The site continues growing, and 15 people now work out of Chesky and Gebbia’s San Francisco loft.

Chesky stays exclusively in Airbnbs for a few months before they can get into a new office space, learning valuable first-hand information about the service.

But something’s still missing.

Brian and Joe fly to New York to try something new.

They go door-to-door and take professional photographs of listings in New York themselves, and find that those listings receive 2x – 3x the bookings.

Airbnb officially launches a Photography program, allowing hosts to automatically schedule a professional photographer to take nice photos of their space. They only have 20 photographers on the platform, but it takes off.

Airbnb secures $7.2 million in Series A from Jeremy Stoppelman, Elad Gil, SV Angel, Y Ventures, Keith Rabois, Greylock Partners, and Sequoia Capital.

In a year, the company had seen 800 percent growth in nights booked, with listings in 89 different countries.

The company hits 1 million nights booked.

Airbnb introduces Social Connections, letting users integrate their social networks for extra verification and general comfort among the community.

At this point, the company is really off and running.

Airbnb makes its first acquisition, buying up German clone called Accoleo.

Airbnb joins the $billion club with a $112 million Series B round from Andreessen Horowitz, Digital Sky Technologies, General Catalyst Partners, Jeff Bezos, Ashton Kutcher, and CrunchFund.

Ashton Kutcher joins the advisory board.

Three days after the announcement of the funding, Airbnb has its moment of truth.

A host by the name of EJ comes home to find her place totally trashed, with everything of value stolen.

Initially, the company refused to help out or assist EJ. That plan backfired.

So the company said sorry and promised to help out EJ. “Anything to make her life easier,” they said.

And then something similar happened to another host. “There were meth pipes everywhere.”

So the company issues an unconditional apology, and announces a $50,000 guarantee to hosts to cover any damages they might incur.

Airbnb kicks off 2012 with an Android app launch. At this point, the company has now had over 1 million guests use the service, with 120,000 listings on the site.

Ahead of the 2012 Summer Olympics in London, Airbnb acquires Crashpadder as part of its international growth push.

As the Airbnb community grows, the team realizes they need to take extra steps to protect users. They introduce the $1 million Host Guarantee.

Hurricane Sandy hits, leaving thousands of people in New York without proper housing. Airbnb encourages NY hosts to lower their rates and welcome people into their space.

Airbnb acquires Localmind.

Airbnb overtakes Hilton Hotels in nights booked. The company now has over 4 million guests on the service, and 300,000 listings in 192 different countries.

Things seem to be going pretty well for Airbnb.

Until NYC-based user Nigel Warren is fined $2,400 for hosting Airbnb guests in his apartment. The company helped pay his legal expenses while fighting the fine.

And so begins a legal tug-of-war that would last for a year between the state of New York and Airbnb. But Airbnb continues to grow, announcing 9 million guests served, up from 4 million just 8 months earlier.

After hitting 10 million guests on the platform with 550,000 properties listed worldwide, Airbnb closes a $500 million Series D round, launching the startup into the $10 billion valuation club.

Airbnb announces a massive redesign to its website and mobile apps as well as a new, “modern” logo. Let’s cut to the chase. It looks like a vagina. Or a butt. (Both? You decide.) In a moment of sheer obliviousness, (or maybe genius) Airbnb prompts users to create their own renditions of the Bélo with a custom logo generator. These were some that we at TechCrunch created.

Airbnb partners with business expense and travel management company Concur, with the goal of capturing more of the corporate travel market.

Airbnb announces a partnership with the cities of San Francisco and Portland as part of an initiative to help communities prepare and respond to emergencies. The agreement states that Airbnb will identify hosts who are willing to help displaced people in the event of an emergency.

Flickr | the.Firebottle

TechCrunch learns that Airbnb is raising a monster round at a $20B valuation.

Much to the delight of Ryan Lawler, Airbnb now lets users view listings on tablets.