Airbnb started in 2008 with only 6 listings and has since grown to over 1.5 million listings in 34,000 cities across 190 countries. It allows homeowners to earn money by listing their underutilized assets, such as houses, while providing travelers affordable accommodation options. Airbnb found early success through partnerships with sites like Craigslist and investing in Google ads. It now has over 3000 photographers documenting listings and a large customer service team to build trust.