Hi I hope you find this useful but you can keep abreast of recent updates on the link below: http://www.seomoz.org/google-algorithm-change
I am following SEL, SEOMOZ, SERT and SEJ.I have not seen any one notified similar stuff.I think its may be a google dance effect or you have to check in your webmaster messages.
Google has no updates after 22nd January panda updation in which he penalized site for the duplicate content.It is based on 1.3% content matching.