From the Othermail FAQ:
OtherMail is a new email address which is perfect for giving out to newsletters, beta invitations and any other low priority email lists. OtherMail collects all of the email which is sent to your @Othermail.me email address and sends you a simple summary email as often as you would like.
There you have it! You can sign up for Othermail here, or learn more here. If you are interested in signing up, I can give you an invite code if you promise to send us some feedback on the service. I’ll very happily give you an invite if you send me an email at email@example.com.