Google Update Going on Check Your site SERP

Each and every one who are receiving end would go for site audit . check for anchor text diversity, back links which has been build yet , which is not unusual whenever such updates are done but one thing which is obvious that Google has not yet said any thing official about this update that will be only clear when it is done complete and have no option but to wait till Google official Statement and detail's of update.All your views and comment's are most welcome.  

Ranking are effected globally from January 17, 2013

It seems like SERP ranking are effected globally from January 17 2013 and one thing which is
quite interesting is sites who have targeted to specifically one country has been affected most
but unlike most sites which are based globally has very good results , yet any official
remark is awaited till now.