If you're struggling to keep emails brief so you can spend more time working and less time writing messages, you might want to check out ShortMail. It's designed to strip down email to its core: simple communication.
You're not allowed to write more than 500 characters, you can't include attachments, and there are no folders. It does almost nothing but aim to keep you answering emails quickly with as few words as possible.
Not coincidentally, you sign up for ShortMail by logging in with your Twitter account. Doing so claims your ShortMail address that you can start using right away. Once you're in, you just write email like you normally would — but with the restrictions previously mentioned. Additionally, you can write email privately or show those messages publicly on your ShortMail page. Aside from search (which lets you search by voice if you want), that's pretty much all there is to it. If you're drowning in email and want to try and simplify, this is a pretty good way to force yourself to do it.