Airbnb features a review system in which guests and hosts can rate each other after a stay. Hosts and guests are unable to see reviews until both have submitted a review or until the window to review has closed, a system which aims to improve accuracy and objectivity by removing fears that users will receive a negative review in retaliation if they write one. However, the truthfulness and impartiality of reviews may be adversely affected by concerns of future stays because prospective hosts may refuse to host a user who generally leaves negative reviews. In addition, the company's policy requires users to forego anonymity, which may also detract from users' willingness to leave negative reviews. These factors may damage the objectivity of the review system.[126][127][128][129]
In February 2011, Airbnb announced its millionth night booked.[34][35] In January 2012, the company announced its five millionth night booked.[36] In June 2012, Airbnb announced 10 million nights booked, doubling business in the previous five months.[37][38] Of these bookings, 75% of the business came from markets outside of the continental United States.
American Airlines, Inc. (AA) is a major United States airline headquartered in Fort Worth, Texas, within the Dallas-Fort Worth metroplex. It is the world's largest airline when measured by fleet size, revenue, scheduled passengers carried, scheduled passenger-kilometers flown, and number of destinations served. American, together with its regional partners, operates an extensive international and domestic network with an average of nearly 6,700 flights per day to nearly 350 destinations in more than 50 countries.[8]

Founded in 1931 as American Airways, American Airlines (AA) is the world's largest airline when measured by revenue and fleet size. A founding member of the Oneworld alliance, AA operates a primary hub at Dallas Fort Worth International Airport (DFW) and has eight secondary hubs at airports across the United States. The airline flies to about 345 destinations in North America, the Caribbean, South America, Asia and Europe. It has codeshare agreements with 15 other carriers, as well as joint ventures with British Airways, Japan Airlines, Iberia, Finnair and Qantas on certain routes. Its fleet consists of 963 aircraft.
Airbnb has grown significantly over the last 3 years. To support demand, the company uses 200 Amazon Elastic Compute Cloud (Amazon EC2) instances for its application, memcache, and search servers. Within Amazon EC2, Airbnb is using Elastic Load Balancing, which automatically distributes incoming traffic between multiple Amazon EC2 instances. To easily process and analyze 50 Gigabytes of data daily, Airbnb uses Amazon Elastic MapReduce (Amazon EMR). Airbnb is also using Amazon Simple Storage Service (Amazon S3) to house backups and static files, including 10 terabytes of user pictures. To monitor all of its server resources, Airbnb uses Amazon CloudWatch, which allows the company to easily supervise all of its Amazon EC2 assets through the AWS Management Console, Command Line Tools, or a Web services API.
Shortly after moving to San Francisco in October 2007, roommates and former schoolmates Brian Chesky and Joe Gebbia could not afford the rent for their loft apartment. Chesky and Gebbia came up with the idea of putting an air mattress in their living room and turning it into a bed and breakfast.[16][17] The goal at first was just "to make a few bucks".[18][19] In February 2008, Nathan Blecharczyk, Chesky's former roommate, joined as the Chief Technology Officer and the third co-founder of the new venture, which they named AirBed & Breakfast.[17][20] They put together a website which offered short-term living quarters, breakfast, and a unique business networking opportunity for those who were unable to book a hotel in the saturated market.[21] The site officially launched on August 11, 2008.[22][23] The founders had their first customers in town in the summer of 2008, during the Industrial Design Conference held by Industrial Designers Society of America, where travelers had a hard time finding lodging in the city.[17][24]