Selected answers from the Dumb SEO Questions Facebook & G+ community.
Alan Bleiweiss: This happens to just one? Or several? How frequently? What rankings - like page one then page two, or page one then page five or page one then nowhere to be found?
Edvin Pauza: It`s predominantly just one keyword, went from 14 to 0 in one day. That page still ranks for others. The url is the same as the keyword, it has a lot of backlinks, some of them have been redirected from one expired domain name.
Arsen Rabinovich: Is it possible that you might have another page competing for this keyword on your site?
Alan Bleiweiss: A site owner recently reached out to me with a similar problem - I wouldn`t offer any specific insights, because it could be many things, and without an audit, it`s a wild guess. Though to be fair, since they thought it was an inbound links issue (I said not likely - Penguin wouldn`t behave that way), I suggested they contact Marie Haynes - she found something odd in the headers, though she wasn`t sure if that was the cause - they changed whatever it was, and the problem happened to go away, though even Marie isn`t sure that was the cause. It may well be Google just being fickle. However you may want to reach out to her.
Alan Bleiweiss: This was a one time change? Or does it bounce in and out?
What does a single keyword jumping in and out of Google`s rankings mean? 
