I'm an avid user of the Gmail platform. I love it for many features that other services don't offer, such as the ability to download e-mail from other POP3 accounts. Google is constantly trying to make the service better, and they are now pushing out an update for how users compose and respond to e-mail.
Instead of going to an entire new window, Gmail will begin to pop-up a compose window in which you can type your e-mail as you normally would. It looks like an oversized chat window, if you've ever used the built-in Gmail chat feature. Google says that the new window is faster and better for multitasking as you can now easily go to other e-mails without closing the draft you're working on.
Google also says the new window is easier to use:
The new compose is designed to let you focus on what's important: your message. The controls are still there when you need them but get out of the way when you don't. We've even added some new features like the ability to easily insert inline images and have more to come.
You can check out a preview of the new compose and reply window today. Google is continuing to add some finishing touches over the coming months, after which they'll "enable it for everyone."