We're all familiar with the recent events and the unwanted publicity Facebook has been getting, but this shows that until they've hit the bottom, they can always sink lower.
This New York Times article talks about Facebook having stored user passwords in clear text! Facebook claims that it's found no evidence of abuse --- as if that justifies it --- but will be alerting its users about this, adding that they won't require users to change passwords. Here's some more on another site.
Facebook's blog has also attempted to provide users with reassurance.
My consolation is that I don't use Facebook or have it linked to any other accounts for authentication.