When you use Google Apps for your domain you might want to forward e-mail for your domain to the Mail-eXchangers from Google so that e-mails get delivered in your inbox at Google and not on the local server.
Why do so? When someone uses sendmail or mails from another domain on the same server, Plesk / Qmail / Postfix do a local delivery to the corresponding domain / e-mail account. Thus the message stays on the same server and never reaches your mailbox. »Read More
