Charter Communications claims a "software glitch" was the cause of an accidental deletion of 14,000 active e-mail accounts. I post this, partially to poke a little fun at the 'accidental' part of it and partially just to further show that human error is the most likely cause in so many large goofs like this.
They claim it was a software error - that they regularly delete inactive accounts and this time 'some' active accounts slipped in. I bet if you were to ask the software company they would most likely say that their software was configured wrong -- by a human. Even routine procedures need to have a RFC (Request for Change) filled out, the process thought through, and a review board look over the change.
Check out the Cnet article here