Emails Stored in Gmail Erased

Google's Gmail is now known around the World as the best free webmail solution - especially thanks to it's storage size and security of data.
Around 60 Gmail users are not quite so happy with the service anymore, after logging in to find all of their emails prior to Dec 18 had vanished.
Google has since responded saying that there had been an unspecified issue which caused their emails to be permanently lost.
I think it's wise to point out that the Gmail service must have at least 10's of millions of happy users still, but it's worth noting an incident such as this.
Noteworthy in particular, as Googles datawarehousing has had such a largely bulletproof record to date - even one of their data warehouses burning down at one point didn't cause any visible data loss or service disruption to users.
It's that sort of massive data redundancy which makes even a small loss of 60 Gmail users emails interesting. Something totally untoward must have caused this, though they are not willing at this time to disclose details as to whether this was a hackers doing, or a technical glitch.
It will be interesting to see whether anything further comes of this.

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I read about this on a few different news sites before posting it, I believe threadwatch and techcrunch were citing The Street's reports.
Its also been covered by CBC news.