Cloud-sharing service Dropbox has acquired the brand-new and already beloved email app Mailbox, which could mean a lot of things for both darlings of Silicon Valley but definitely means a lot more users will be able to jump in on the rollout of one of the most instantly popular iPhone apps for email on the market.

So, you can all breathe a sigh of relief, because Dropbox isn't killing the app, like some other tech startups turned tech giants that have been buying up little all the wonderful little mail apps (ahem, Sparrow). To scale up Mailbox "gracefully," there has been a waiting list for access. And as of right now, more than 500,000 people are still on hold, which kind of stinks for people who have read all the favorable reviews and want to sign up. Thanks to the famed infrastructure of Dropbox, however, the folks at Mailbox can now speed up the sign-up process: "We felt we could help Mailbox reach a much different audience much faster," Dropbox's CEO Drew Houston told Digit's Jessica E. Lessin

Other than some benevolent move to get Mailbox onto more smartphones, Dropbox says it will use the app to help with its email attachments. Maybe that means people will be able to access Dropbox files from within Mailbox? Dropbox also hinted at some app design envy: "It was simple, delightful, and beautifully engineered," Houston said. So perhaps we'll see a redesign soon.