Mailbox e-mail client fills 1M reservations, adds 'shake to undo' in update

In a post to the official Mailbox blog, the company also said it had finished moving into its new office after being acquired by cloud storage giant Dropbox last week. According to reports at the time, the popular e-mail client was picked up for between $50 and $100 million.

Mailbox reached the one million member mark after just six weeks of availability, with demand remaining high for access to the iPhone-only app. In an early look, AppleInsider found the client's unique "to-do" list interface to be an effective method of sorting and managing e-mail messages.

Now added to the software's feature set is the new "shake to undo" capability, which takes the idea of undoing text changes, as seen in Apple's iOS, to app-wide e-mail management.

While a queue still remains for Mailbox, reservations can be placed through the free to download app and will be filled in the order in which they are received.