Tired of waiting around for Gmail to send messages? Sending many messages at once, but can’t begin to use your email again until they’re all sent? Now you don’t have to worry anymore with the new Gmail Labs feature, called Background Send, which will send messages in the background. You can use Gmail regularly while you send either one or hundreds of emails. No matter how long the sending process will take, you can instantly access your email again after sending your messages. A notification at the top of your inbox will show you that your messages are still sending in the background.
If all the messages are sent, you will get the message sent notification. Otherwise, a red error will popup notifying you that there was a problem sending your message. You have the opportunity to fixit now or later. You don’t have to stop doing what you’re doing just to fix the problem email. However, you should check this problem before you close Gmail, because chances are this problem isn’t going to show up next time you startup Gmail.