If you’ve been Twittering long enough, you may be vaguely aware of a feature called “Direct Message” (DM) that allows you to send a private note to another user. I say “vaguely” because quite frankly it’s truly, hopelessly broken, and nobody uses it unless they absolutely have to. I personally only use it if I have no other way to get in touch with someone, and I make sure to exchange email addresses or phone numbers as quickly as possible.

Why does Twitter’s DM feature suck? Let me count the ways:

1. It uses the same eventually-consistent backing store and event model that the main tweet system uses. DMs get to where they need to go… just not quickly… or in order… and differently on each device attached to your Twitter account. This would be like sending someone a text message or an email and not having any confidence in the timeliness of its delivery. It makes it extremely difficult to have a quick, impromptu chat conversation with someone.
2. It’s limited to 140 characters. Okay, I get it, it has to be shorter than the maximum length of an SMS and it’s one of the hallmarks of the innovative microblogging platform. But it’s not really a tweet; can’t Twitter break it up into 140-character chunks on the fly? Just to indulge the three remaining users who still interact with the service via text message?
3. Once I read a DM on one device, say my phone, it’s been read. It doesn’t need to be read again. I don’t need to see the “unread” DM on my workstation, my laptop, etc. and have to click through to clear it. What’s even more irritating is sometimes I’ll be alerted more than once about the same DM on the same device. Not cool, Twitter. Not cool.

Robert Scoble over at Rackspace has a great rant about the direct messaging features of Twitter and Facebook, more along the lines of the similarities and limitations cf. email of how they (don’t) interact with your other communications channels. Consider it suggested reading.