Launch HN: Promoted (YC W21) - Search and feed ranking for marketplaces
I&#x27;ve worked on ranking in travel before, and you&#x27;d be amazed at how terrible ranking is in pretty large companies with a huge incentive to improve things.  You&#x27;d also be amazed at how long it takes to sign a contract with someone that says &quot;we&#x27;ll increase your conversions by ~15% (and your revenue by literally millions) in exchange for a small portion of your increased profits.&quot;<p>Pretty curious about how well you can build a generalized solution and still get uptake from SMBs.  I&#x27;d think that marketplaces would tend to want to keep that kind of expertise in house, but I guess my experience shows that there are some less eng-focused companies that would pay for that kind of thing.<p>&gt; When we started, we were shocked at how little marketplace companies measure anything.<p>For the travel company mentioned above, our model was built on hotel bookings only.  That is, they gave us a list of every booking made on their platform, and then at search time they gave us the parameters of the search (city, dates, incoming flight) and hotel availability, and we were supposed to return the ranked list of hotels.  Not in that training set: anything about unconverted searches, what hotels were shown to searchers at any point, or anything about the customers.  Again, our model built on super sparse data outperformed their ranking by ~15% over a period of multiple years.  (We had even better results over shorter time frames with another customer that never signed a contract.)  I kept on telling people that these (Europe-based) companies could have signed a reasonably competent data scientist for like $50k&#x2F;year, outperformed our models within 6 months or so, and saved themselves 6 figures&#x2F;year.