Enterprise microblogging, in particular, makes e-mail and IM more useful.

But choosing the proper communications mechanism now can be confusing for people. Many have tried to answer this question of IM vs. microblogging vs. e-mail, but if they had done so adequately, people wouldn’t still be asking about the differences. So now, with absolutely no presumptuousness, here is my stab at it.

What e-mail is good for:

1. E-mail is good for closed communications, addressed from one-to-one or one-to-few. The information being traded you don’t feel is relevant — and never will be relevant — to a larger group.
2. Communications that are granular in focus or formal. Some examples: A letter to a boss or HR, or a thank you note to your friend or grandmother.
3. Communications where people live in separate networks, and the hassle of creating a new network to support their communications doesn’t seem worth it.
4. Everybody has it.
   
5. Platform independent.
6. Accessibility (it’s free on the Web) and push notification means a huge swath of people have it on their phones.

What microblogging is good for:

1. Open conversations. With microblogging, you post information into the stream openly for people to see, not just the precious few you remembered to CC in an e-mail.
2. Awareness. General status updates are very helpful on the day-to-day at work (“heading to meeting with the client” or “editing the press release”). IM isn’t as good for this, either, since status is more a state of being (“busy” or “available”) and has less context. Even customized status in IM isn’t very visually appealing because it’s not in a flow-based design.
3. Opt-in model. People can subscribe to your updates. With e-mail and IM, you have no choice in the matter. (“push versus pull” is in the industry jargon for this).
4. Discoverable. Microblogging is searchable and captures information for everyone in your network to see. With e-mail, people can only search for things in which they were addressed in the message.
5. Forcing succinct thoughts. While there will be more debate about the 140 character limit of microblogging messages (as fashioned by Twitter), the constraint keeps musings at a reasonable length and prevents the long rant e-mails that generally don’t add much to the collaborative process (you see a similar thing happen in forums). Microblogging actually can be a good way to gauge what conversations and ideas deserve longer form, and someone can post a link to a web page, wiki or blog where people who are interested can engage more deeply.
6. Doesn’t turn people into information janitors. In both e-mail and microblogging, you will see information and noise not relevant to you. The main difference? Since microblogging is a flow-based app and less structured, information you don’t feel the need to address can keep on moving, eventually going out of sight and out of mind. With e-mail, every message requires attention in some way if you want to keep your inbox a usable place. That doesn’t necessarily mean you must reply. But you will spend time deleting, unreading or putting messages into nice tidy folders. Email is, after all, beholden to a paper/filing cabinet metaphor. (Could be the reason Gmail is the only usable e-mail service since it departed from this slightly).
7. More casual communications etiquette. There’s more pressure to respond to both e-mail and IM than microblogging. If someone you know or work with decides to e-mail or IM you, you feel inclined to respond even if you’re not interested or don’t have time. How many times do you say, sorry I haven’t responded to your e-mail? With microblogging, the app’s design causes people to — pardon the hackneyed expression — go with the flow. If you don’t respond, it’s nothing personal.
8. Ability to get answers without interrupting people. Ties into point #3 and #7. When you encounter a business problem and you don’t know who to ask, microblogging is great for questions because of this opt-in model. The people who don’t know the answer let it pass; the person who does replies for everyone to see. That reply is also searchable for the future.

What IM is good for:

1. One to one conversations. Similar to e-mail. Think your typical IM chat with one co-worker or family member where information you share is only pertinent to each of you.
2. Banter. We like to talk about the weather, last night’s game, the show we saw, or the general things that we’d talk about if in person. In fact, it’s better that a lot of this stuff go into IM rather than disrupt the stream in microblogging and e-mail with crap no one would want to search for later.
3. Close relationships. We IM with people we know pretty well, either personally or in a business context. For the latter, our business would have to be frequent to warrant IMing.
4. Really half-baked idea generation. While I like to use microblogging to tap my peers expertise and build on an idea, sometimes I need to work an idea out by spewing prose onto a page with a couple colleagues in real time before I can condense that thought into a simple sentence. IM is great for this.
5. Pairing. I don’t mean two developers sitting at the same computer. If you’re working on, say, a wiki page or a blog post with a co-worker, and want to discuss the next thing to add, IM is nice alongside the app.

The choice between all of these technologies, and when to use them, could evolve over time. I’m curious to hear people’s thoughts.

/cgl