David Steven has been on the case and his frequently updated post is well worth reading.
Other articles are available at the BBC from Rory Cellan-Jones, the Guardian and at 5CC who puts the story in a wider context.
In short, the Mail ran this story prominently on its website and in a two-page spread in the print edition:
It was based on some online research by former cop Mark Williams-Thomas.
But he didn't do that research on Facebook, as the Mail's headline claimed.
The description of having people trying to chat with him within 90 seconds didn't even sound like the way Facebook works.
According to Williams-Thomas, he was sent a draft of the article by the Mail but they ignored his requests for the inaccurate references to Facebook to be removed.
Mail Assistant Editor Charles Garside blamed it on 'miscommunication'.
Given that in the past the Mail has accused Facebook of giving you cancer, destroying your marriage, raising your insurance premiums, rotting your children's brains, making you fail exams, putting you in a coma, causing riots, making you commit suicide, promoting gangster culture and causing you to be stabbed and strangled that seems unlikely.
Look at the front pages from Tuesday and Wednesday:
The Mail has a bizarre, obsessive hatred for Facebook and will try and blame it for whatever it can, and in the wake of the Ashleigh Hall case, stories about teen girls 'meeting' pervy men online were the order of the day.
The website headline was soon changed, and all references to the site removed from the text. But the Mail couldn't work out how to change the URL for some time, and so the slur remained.
And, apparently, all attempts by Facebook to post correcting comments were rejected by the Mail's moderators.
With Facebook threatening to sue, the Mail added this 'clarification' to the article:
In an earlier version of this article, we wrongly stated that the criminologist had conducted an experiment into social networking sites by posing as a 14-year-old girl on Facebook with the result that he quickly attracted sexually motivated messages. In fact he had used a different social networking site for this exercise. We are happy to set the record straight.
And another clarification (not apology) was published on page four of today's newspaper:
In an article by a criminologist yesterday, we wrongly stated that he had conducted an experiment into social networking sites by posing as a 14-year-old girl on Facebook with the result that he quickly attracted sexually motivated messages.
In fact he had used a different social networking site for this exercise. We are happy to set the record straight.
Three things stand out. Firstly, note how the printed clarification blames 'an article by a criminologist' rather than an article by the Mail's Laura Topham. This feeble blame-shifting is all too common in clarifications and apologies. Why can't the Mail just admit they got it badly wrong? And why can't they just say sorry?
Secondly, although the original story was prominent on the Mail's homepage yesterday, the printed clarification can only be found by searching for 'facebook'. 'Due prominence', as the Editor's Code says, should mean it was mentioned from the homepage like the original.
Thirdly, when faced with the threat of court action by a huge worldwide company such as Facebook, isn't the Mail's back-peddling notably quick to appear.
Compare that with the member of the public who complained about Richard Littlejohn blaming Eastern Europeans for 'most' robberies in Britain, where the Mail took six weeks to reply to the PCC over the issue.
According to Channel 4 News' Ben Cohen, Facebook have rejected the Mail's apology (which it wasn't, anyway) and plan to go ahead with their legal action because of the damage to their name caused by the Mail article.
Let's hope they do, so the Mail can be properly held to account.