You can now choose the reply-to address in Gmail for your various email accounts. My public email account (the one I use to sign up for stuff etc) forwards all email to my private account. This new feature now allows me to choose what the reply to address will be for all my email accounts. So if someone sends an email to email@example.com and I respond to that email from my private account I can choose what the reply-to address will be. If you forward other email accounts to your Gmail you'll want to use this.