Mailbox, which will initially be compatible only with Gmail, aims to keep your inbox clean by allowing you to use swipe gestures to quickly move each email out of your inbox by deleting it, archiving it, assigning it a category or - perhaps most interestingly - setting it to pop back into your inbox later.
When you sign up to reserve your copy of the free app, Orchestra sends you a text message with your reservation number, together with a code. Once the app is available for download, you'll need to enter your code to complete the download.
Business Insider observes that Orchestra has an interesting link to Apple: one of the company's software engineers is Adam Cue, son of Apple Senior Vice President Eddy Cue, who is responsible for iCloud services - including email. Business Insider suggests that the relationship is likely to put Mailbox on Apple's radar as a potential acquisition, but it is unclear whether Apple has any actual interest in Orchestra's ideas for email management.