Yahoo is making a personal assistant and mobile search app that will compete with Apple’s Siri, Google Now and Microsoft’s Cortana. The app, codenamed “Index,” will be able to pull information from a user’s email to provide the most relevant search results. It will most likely be ad-supported and the company is aiming to complete a pilot version of the app this year. Yahoo executives hopes this app will be able to take some share of the mobile search market from Google.

Index is supposed to stand out from other similar apps because Yahoo has had a longer relationship with its users. A source told Business Insider, “Gmail users have only had their accounts for 10 years. Yahoo has many 20 year old accounts. Back then people used to email themselves a lot — store things. To surface that kind of data usefully is exciting.”

That means that Yahoo’s mobile search app will be able to use email accounts to make sure they are surfacing the right kind of results. For example, if a user searched “JFK,” the app would be able to figure out that the user means the airport because their email inbox has tickets for a flight going to JFK.

Like other personal assistant apps, Index won’t just provide search results. It will also let users complete related tasks like set reminders and book reservations.

The new app might help Yahoo break into the mobile search business, but CEO Marissa Mayer may have her sights set even higher. She is trying to revamp Yahoo’s Web search engine. Recently, she renegotiated Yahoo’s deal with Bing so that only 51 percent of traffic will be outsourced. To rebuild the Yahoo search engine entirely could cost $500 million per year.

Some former Yahoo executives think Mayer should outsource all of their search traffic and save $1 billion.