My intention this week is to write about Shortmail, a new email service. But to set the stage, I need to share three examples of Personal Email Policies I Greatly Admire.

Example 1: When danah boyd (yes, it's meant to be all lowercase) needs a break from digital communication, she goes on an email sabbatical. Her mail server sends all incoming messages to the trash, and an auto-responder lets all would-be correspondents know that while danah's away, their messages will not be received. As danah wrote on her blog, "You cannot put anything in my queue while I'm away (however lovingly you intend it) and I come home to a clean INBOX."

Example 2: I have a friend whose email signature includes the following expectation-setter: "I respond to short emails at 11:30am and 3:30pm daily. I reserve Mondays to respond to longer emails or in-depth responses - that way I have the time for a proper answer."

Example 3: A while back, I heard about five.sentenc.es (and its siblings two, three, and four.sentenc.es), "a personal policy that all email responses regardless of recipient or subject will be five sentences or less." The idea here is that you adopt this policy, link to it in your email signature, and don't allow exceptions.

Now here's the thing: I love all of these ideas. But only on paper.

Practically speaking, I can't imagine putting any of these into practice. Maybe it's a lack of guts. Maybe it's a lack of discipline. As much as I admire these ideas, the closest I've ever come is the standard out-of-office message.

And thus is my initial reaction to Shortmail, a new email service from Baltimore-based 410Labs. I like the idea, but mostly on paper.

Shortmail will be immediately familiar to anyone who's used a web-based email service like Gmail, Hotmail or Yahoo Mail. But as its name implies, the major difference has to do with length. Shortmail imposes a limit on how long your messages can be: 500 characters. This clearly seems like a page borrowed from the playbooks of pith-obsessed micro-messaging services such as Twitter and Canadian-based StatusNet.

Not only does Shortmail restrict the length of outgoing emails, it imposes the same 500-character limit on incoming messages. If you send me a message that goes over the limit, Shortmail will bounce your email back along with a notification that it's too long. You're then given an opportunity to edit your message to fit within the limit. This is the digital equivalent of saying, "Get to the point."

I understand why that might be appealing, but I can also see how that might come across as, well, rude. An @shortmail.com address effectively says, "Play by my email rules, or don't play at all."

Beyond message length, Shortmail has taken other cues from social networking and micro-messaging services. Its other big difference has to do with sharing. On a one-to-one basis, email has historically been private by default. But Shortmail shakes this up, adding a public option. For example, I can send you an email, mark it as public, and in addition to showing up in your inbox, it'll also be published to the web. For example, here's a public email conversation I had with Shortmail creator Dave Troy.

Public messages sent through Shortmail are clearly labeled as such. Still, the idea of "public email" is a pretty big paradigm shift. It's not hard to imagine inadvertently publicly publishing a message intended for a private recipient.

Of course, Shortmail is just one reaction to the decades-old love/hate relationship many of us have with email. Last month, Chris Anderson (of TED conference fame), published the Email Charter, which outlines 10 rules to "reverse the email spirals" — rules that cover principles like writing better subject lines and avoiding unnecessarily open-ended questions. The Email Charter isn't a piece of software or a web service. It's more of a personal pledge.

Anderson's Email Charter (and the aforementioned sentenc.es policies) take a Gandhi-esque "be the change" approach to email. Shortmail, in contrast, imposes its vision of better email on all messages sent through its service.

Beyond length-limitation, I wonder about Shortmail and the "one more thing to check" factor. I mean, I already have a handful of email accounts. And Twitter accounts. And a barely used Facebook account. And now, a Google+ account. Do I really need yet another inbox to check on a regular basis? If the goal is to spend less time dealing with email, having a separate account just for short messages seems a bit counter-intuitive to me.

While it's interesting to see how the form and function of contemporary social media tools are rubbing off on the decades-old system of email, for me, Shortmail is a bit too much like danah boyd's email sabbaticals: something I wish I could pull off, but probably never will.