Yahoo Mail’s search now returns 150% more relevant results

Yahoo today revealed more information about the advantages of the updated version of the search technology in Yahoo Mail, which recently became available on the web, Android, and iOS.

The new user interface draws on a new system for ranking emails based on relevance. But people still often rely on recency in order to find the emails they’re looking for, so the relevance system has not completely replaced the chronological search results. Emails that Yahoo thinks are more relevant are just at the top of search results. Key factors include whether a user has opened or starred an email, and whether it includes links or attachments.

Additionally, Yahoo has employed an auto-completion system that leads to richer search queries, because people tend to type so little into the search box. To figure out what to suggest, Yahoo takes into consideration search history, what’s in a user’s inbox, and search history for all users, as well as gender, age, and location.

“The combination of all these signals improves the quality of the suggestions by up to 150 percent when considering the average rank of the clicked suggestion,” Yahoo Research director Liane Lewin-Eytan ​and vice president Yoelle Maarek wrote in a blog post. Maarek will talk about the underlying technology today at the World Wide Web Conference in Perth, Australia.

Of course Yahoo has been working on search for many years, as has Google and Microsoft. But searching for emails is different from searching for content on the web. Maarek and Lewin-Eytan explain:

When searching your mailbox, you are typically looking for a message that you have received and most probably read. You try to remember the name of the person who sent it to you or some distinctive words in the message. In other words, you try to re-find a given message, while in Web search, by contrast, you try to discover new information.

The new search system arrives a few months after the reorganization of Yahoo Labs. Yahoo Mail itself has more than 225 million monthly active users.

For more on Yahoo Mail’s state-of-the-art search technology, you can check out two new papers on the subject.