Best Answer torka , 06 February 2013 - 09:55 AM
Beyond that, technically, the folks at Google put through more than 400 algorithm updates every year, so there are changes every day. (If you do the math you see there are actually sometimes more than one per day.) Most of these are minor and don't get mentioned in the press, but that doesn't mean they have no effect on any sites. It's possible that the one you're looking at got caught up with one of these minor every day tweaks.
Just because nobody specifically mentioned an big update around about the time you saw the change, that doesn't mean there was no update then. It just means the update(s) that almost certainly were taking place were routine, not "big" enough to warrant mentioning.
--TorkaGo to the full post