SaneBox

App Description
SaneBox is a web-based service that works with most email services, including Gmail, Exchange, iCloud, and many IMAP providers. Its basic function is to automatically filter incoming messages. It leaves important messages in the inbox and automatically moves less pressing ones to a @SaneLater folder you can check at your leisure.
Training SaneBox
Most of the time, SaneBox’s algorithms automatically determine where an email belongs. You can train SaneBox simply by dragging emails to their most appropriate destination. For example, if a less-than-important email ends up in your inbox, drag it to the @SaneLater folder to let SaneBox know that similar messages should be filtered in the future. Similarly, if an important email ends up in the @SaneLater folder, let SaneBox know of its importance by dragging it to the inbox.

Tracking Responses
When you send an email, you can optionally cc or bcc something like 3days@sanebox.com or 1week@sanebox.com, and SaneBox will send you a notification by email if you haven’t received a response within the specified time. At this point, you have the option of “snoozing” the reminder (e.g. asking SaneBox to remind you again in one more day if no response has been received by then) or may opt to send a follow-up message to remind the recipient that you’re still waiting for a response.
If you use this Response Tracking feature, you’ll spend less time creating and tracking “Waiting” items in OmniFocus. In cases where SaneBox alerts you that your recipients didn’t get back to you promptly, OmniFocus can be used to remind you to follow up with them.
