ABC News has just released this statement explaining how blogger Wild Bill of Passionate America was able to learn the real screen name of Mark Foley's Instant Message correspondent:

On Friday, ABC News published instant messages between a former page and Congressman Foley with the IM screen name of the teenage victim redacted. Immediately, we discovered that in one instance, the screen name of the teen on one IM exchange had not been properly redacted. ABC News immediately took down the posting [version 1], redacted the screen name and re-published the posting [version 2]. We certainly believed that we had taken care of the issue quickly. Last evening, after an inquiry from Matt Drudge, it came to our attention that a blogger was able to access our deleted file [version 1] by typing in a slightly modified web address. To be clear, no one visiting our website would have simply stumbled on the old version. We thank the blogger and Drudge for bringing this to our attention.

By "immediately" ABC apparently means, "five days after the fact," according to the Drudge Report headline for this story.

Background:

ABC alters Blotter entry.

ABC misstates age of IM recipient.