Suzanne Tindal writing for ZDNet.com.au:

The Australian and Music Feeds this morning flagged a spreadsheet, containing around 1500 BigPond email addresses, postal addresses and telephone numbers, that was freely accessible online. [.. Telstra] believed that the spreadsheet had been created by a consultant to use in training, and not for a malicious purpose.

It's often the case privacy and security breaches occur as a result of unwitting users, rather than someone malicious on the outside. In any event, at least they didn't display cleartext passwords again, right?