A Google Update?
This bit of news falls into the ‘better late than never’ I guess. It seems that Google pushed through update last weekend that has affected a number of people.
One keyword phrase that we’re interested in has certainly had a bit of a shake up and we’ve been affected but we’re not particularly worried and nor should you be if you’ve been affected too. Just be patient and in two weeks, or even less, you could see the SERPs revert to what they were.
Of course if it makes you feel better then by all means panic and run around in ever decreasing circles 