I havent experienced the same thing. By the way how do you check your keyword rankings? Do you check them directly on google or are you using a tool? Personally, i'm using a tool and there are instances that when i check my rankings using the tool, most of my keywords drop! But when i check on google directly, my keywords are doing fine.
Something strange has been happening and you aren't the only one to notice. My blog has just been ranking really high for wacky key terms to suddenly drop out again. I have also watched a site drop into thin air and it hasn't come back. Thankfully it isn't one of mine just yet.
I've spoken to a few people who have all said their SERPS have been fluctuating over the past week, and some sites haven;t been crawled as often as usual....
my site went from 15th page to 1st for my primary keywords ))))))) plus hundreds of other keywords on page 1-2