For all of Yahoo's corporate problems, it still has one of the world's most widely used e-mail products (and is possibly the market share leader in the US according to ComScore statistics from late last year).

But Yahoo clearly lacks some of the technological advantages enjoyed by rivals Google and Microsoft, including having an offering in the fast-growing area of cloud storage. Google integrated Google Drive with Gmail and Microsoft integrated SkyDrive with Hotmail. Yahoo has nothing comparable.

Instead of creating its own cloud storage service, Yahoo decided on an approach that may end up being better for its users—a partnership with Dropbox. Starting sometime today, Yahoo Mail customers will be able to use Dropbox within webmail.

"You can add stuff from Dropbox to any e-mail message and save attachments back to Dropbox, too," Dropbox wrote in a blog post. "Since this integration is Dropbox-powered, you can even send that big album of vacation pics without worrying about the 25MB file limit."

The integration will be available in Yahoo webmail in English, French, Spanish, German, and Italian. Yahoo users not yet registered for Dropbox will be able to create a Dropbox account from within Yahoo Mail, Yahoo's blog said.

The Dropbox integration looks as if its geared toward desktop Web browsers, but Yahoo CEO Marissa Mayer is also trying to bolster Yahoo's presence on mobile devices. Yahoo's latest move on the mobile front was to purchase Summly, a mobile news app maker founded by a 17-year-old entrepreneur.