Mail Pilot for iPhone (US$14.99, universal) is the Kickstarter-funded app that hopes to reinvent our relationship with the incessant demands of email.
Much like competitor Mailbox (our review here), Mail Pilot lets you sort messages by the date you choose to deal with them. There's also extensive gesture support, so feel free to swipe your way to Inbox Zero. Unlike Mailbox, Mail Pilot does not route your mail through its own servers, which might be a comfort to some. It also supports more than one email provider.
