Jeff Atwood is right. Email = Efail.
There are lots of small problems with email, but its biggest disadvantage is fundamental: it is a one-to-one communication.
The problem with one-to-one processes is they are usually inefficient. They completely consume both parties involved while benefiting no one else. Put another way: there's no multiplier.
If I write you a really useful email, you'll benefit some fixed amount. If I want to be twice as helpful, I have to write an email that's twice as useful. But if instead our communication happens publicly, in a one-to-many way, that original email becomes twice as helpful as soon as one other person reads it. I've got no prayer of making my email 1,000 times more useful, but Google might easily funnel me a thousand people looking for the information I wrote about.
This multiplier effect is powerful, and it's in full-force at Twitter.
I was in the market for a hosting company recently. A Rails app I'm building needed a good home, and I set out to look around the neighborhood.
A friend recommended Slicehost, and after browsing their site I was almost sold. On a whim, I clicked a link to their Twitter feed.
Check that out. Every entry is an @reply to one of their users. When I clicked through to the people they're addressing, I found that the person usually hadn't explicitly ask for help from Slicehost, or addressed them directly at all. People had usually broadcast that they were interested in the service, or had recently joined. The Slicehost folks had been searching all feeds for references to their company and chimed in with useful info and words of welcome for new users.
Two important things to notice here:
1. People who didn't explicitly ask for help are getting it. Slicehost has an opportunity to overdeliver for their clients and create passionate users of their service.
2. Everyone else can see this happening!
These facts have tremendous impact. First, if you create passionate users they will talk about their experiences, and that gets you even more users. Remember that I was considering this company in the first place because of a friend's recommendation.
Secondly, I was able to see first-hand that Slicehost is passionate about good service. Hosting companies are a near-commodity these days, and personalized, thoughtful service is a real differentiator.
Finally, notice that if these communications had been locked up in e-mail, neither of the benefits above could have been realized.
I signed up with Slicehost shortly after.
Twitter one. Email nothing.
(If this post inspires you to sign on with Slicehost, doing so through my affiliate link would be groovy.)