Dropbox to acquire email management startup Mailbox

Dropbox Inc said on Friday it would buy the startup behind the hot email management app Mailbox, signaling its intent to aggressively expand its features beyond file storage.

Terms of the deal were not disclosed.

Mailbox was created by a team led by Scott Cannon and Gentry Underwood, who had raised $5.5 million in venture capital funding from Charles River Ventures and others.

"After spending time with Gentry, Scott, and the team, it became clear that their calling was the same as ours at Dropbox-to solve life's hidden problems and reimagine the things we do every day," Dropbox co-founders Drew Houston and Arash Ferdowsi said in a blog post. "We all quickly realized that together we could save millions of people a lot of pain."

Valued at $4 billion by its investors, Dropbox has said it could become a Web powerhouse by adding features to its core storage function. In the past year, for instance, Dropbox has added features to help upload and organize photos.