"The ability to skim them on a phone or a tablet can be a real challenge — we want easier ways to identify what's important to us," said Adam Cahan, senior vice president of mobile and emerging products, in a statement.
As part of the acquisition, Summly will be shutting down its own app, but Cahen said the technology will be implemented into Yahoo's mobile services soon. The now 17-year-old D'Aloisio—who is from London— will also be joining Yahoo's team.
(Read More: Meet the 17-Year-Old Who Is Reinventing News )
D'Aloisio said in an interview on CNBC in November that Summly had hundreds of thousands of dollars in funding just weeks after its official launch. Notable investors and advisors include Ashton Kutcher, Yoko Ono and Zynga CEO Mark Pincus.
"The only reason this has all happened fundamentally is the idea and the product is really useful and I think in today's world, there's so much information and information overload that Summly is trying to attack this from a very pragmatic and different angle," D'Aloisio said on CNBC's "Squawk Box" in November.
Summly is the latest in a string of acquisitions by Yahoo since Marissa Mayer took over as the CEO last year.
Last week, the company announced that it was purchasing Jybe—a start-up focused on personalized recommendations—started by former Yahoo employees. Yahoo also closed Jybe's app as part of its acquisition, but also plans to integrate Jybe's technology into the Yahoo platform.
(Read More: Yahoo Gets Personal With Latest Acquisition—Jybe )
Yahoo also recently purchased Stamped, a mobile app that let users review and share their favorite things; OnTheAir, which is an app that enables webinars that can be watched via a live stream; Snip.It, a social media website; and Propeld, which was a start-up focused on making local recommendations.
(Read More: Yahoo's Mayer Makes Her First Deal )