From your email's manage page you can view overall email statistics, subject line test statistics, view the email's content as well as the raw HTML and send a test in the "View Email" tab, and view the targeting used.
You can add tags to the email with the "Edit Tags" button. Tags don't do anything but categorize your email. You can view the tags on this manage page or in your group's manage page. You can also create a tag when adding tags in this way using the "Add New Tag" button.
Click the "Duplicate This Email" button to make a copy of the email, including content and targeting. Click the "Duplicate With Exclude" button to duplicate the email, exclude the first email from the duplicate, and remove the random limit. (This is useful when doing email testing.)
If the email hasn't been sent, you can refresh targeting as well by clicking the "Refresh Targeting" button and generate a new count.
You can also stop emails mid-send from this page.