If you are the kind of person who can’t help but look when you drive by an accident scene, DMFail is for you. The site, which has been all the rage on Twitter for the last few days, shows direct (private) messages that were sent improperly on Twitter and are therefore public.
If you want to send another Twitter user a message that only she or he sees, you type [D + username + message]. But a lot of people accidentally type DM (for Direct Message) instead of D, and when that happens you pay the price of having your message pop into your Twitter stream for everyone to see.
DMFail grabs all those messages and reprints them on its site for everyone to see, which can be quite a horrible experience for the people involved. Thus the accident scene analogy.
It would be fairly trivial for Twitter to change things so that DM also sends a private message, but so far they haven’t. On average, a couple of messages per hour over all of Twitter end up hitting DMFail.
Direct messages on Twitter don’t seem to be all that secure in general. They’re available to third parties through the API, for example, and there has been at least one case where confusion led to making some direct messages public.
Anyhow, from now on I’m just going to start all my Twitter messages with DM. I suggest you do the same.
Update: Twitter will make changes to allow DM to send private messages too.