By Surabhi Gupta
A marketplace search is when you go to a specific website, such as Airbnb or Amazon, to hunt for a particular product, service or, in Airbnb’s case, property. As Airbnb engineering manager Surabhi Gupta explained in her recent OpenAir 2015 talk, there are three main reasons why marketplace search is more challenging for engineers than traditional search (such as on Google or Bing):
1. Conversion takes more than a click.
With traditional search, a user types a keyword or phrase, reviews the results, then clicks on the most relevant result. With a marketplace search on Airbnb, other steps sometimes must happen before a user ‘converts’ (makes a booking).
For example, a user may identify a listing she likes but wants to ask the host questions. The host can respond to the questions and accept the reservation; answer the questions but reject the booking; or not get the chance to answer the questions, and the guest moves on to another listing.
Airbnb’s search ranking uses machine learning to try and predict a final booking outcome, in order to help the guest easily find the best listing. To accomplish this, the Airbnb search team modeled the five intermediate states it cares most about: Impression (the displayed search results); Clicks (did the user like a result enough to click on it?); Accept (the host accepts the guest’s reservation); Reject (the dates don’t work out); and Booking.
Each state is given a score based on past user actions. By serving up search results influenced by how likely the user is to book the properties displayed, Airbnb has achieved “a huge booking gain,” Gupta said.
2. Decision making requires a lot of context.
Because Airbnb properties are unique, users need a lot of context to decide whether a listing is right for them. Airbnb’s engineering team has experimented with different ways of presenting information to users. For example, because location and price are the two most important requirements, Airbnb has given users information about neighborhood characteristics displayed on a city map as well as price histograms.
3. The supply is perishable.
Airbnb listings are “perishable” because they are unique properties whose availability comes and goes. To prevent users from reading about a property only to discover it’s not available when they want it, Airbnb built a real-time information infrastructure using MySQL databases, a centralized index, and Ruby on Rails. (Jump to 15:53 in the video for more details.)
Going forward, Airbnb wants to make it easier for users to pick up exactly where they left off when returning to the site; add more personalization options; and obtain a deeper understanding of its listings in order to give guests “the best possible experience” when matching them with hosts.
Check out all of our open source projects over at airbnb.io and follow us on Twitter: @AirbnbEng + @AirbnbData
Originally published at nerds.airbnb.com on August 4, 2015.
