Dropbox announced today that it's picked up Mailbox, the new iOS email app and queue-waiting simulator.

Mailbox will remain a stand-alone app rather than get wrapped into Dropbox, with the acquisition's goal aimed at helping Mailbox grow.

"Rather than grow Mailbox on our own, we've decided to join forces with Dropbox and build it out together," read a blog post by the Mailbox team.


Growing pains

Mailbox's growth has been the email app's biggest source of buzz, but not for how fast it's growing.

In order to ensure Mailbox's servers can accommodate all users, there's a queue interested parties need to jump in before gaining access.

While waiting in line, the app offers a counter to show both how many users are ahead and behind them in line. At the time of the merger with Dropbox, there are more than 500,000 people waiting about.

Despite the wait, Mailbox is gaining in popularity, with CEO Gentry Underwood telling The Wall Street Journal that it's already taken 1.3 million reservations since the service started in February and delivers 60 million emails each day.

Boxes within boxes

Dropbox said the acquisition came about because the two companies have an eye on the same things.

"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 CEO Drew Houston said in a statement.

"Dropbox doesn't replace your folders or your hard drive: it makes them better. The same is true with Mailbox, it doesn't replace your email: it makes it better," he added.

All 14 members of the Mailbox team will now join Dropbox, though no price has been given for the acquisition.

While past Dropbox acquisitions have been more about buying the technology and closing the service, Mailbox will remain an active stand-alone service. At least, that is assuming you can get in.