Gmail has reinvented itself over the years to integrate new Google services, but the basic task of composing a message has stayed much the same. As of today, that will be changing: in a blog post, Google announced that instead of a dedicated screen, the Gmail Compose tool will now pop over the inbox like a Chat window. That means referencing other emails will no longer require opening a separate window or saving the email as a draft and re-entering it — something that we imagine most web users will find quite useful. It also means you can write multiple messages at a time, although we're not sure how many of those windows can be comfortably fit on a screen.
Some other new features are coming as well: attached images can be quickly added inline, profile images will show up for recipients, and recipients can be dragged and dropped from the To, Cc, and Bcc fields. While it hasn't rolled out to us yet, it looks like Google is building a more organic style of networked messaging than its failed Wave service, recognizing that people want to pull from other sources — including their own inbox — while still sending traditional emails. The tool will be rolled out as a preview today; Google says that the final version will include more features and be turned on in the coming months.
Update: If you're curious about how the new system works, you can check out Google's new help page for it.