And then nowhere in site for that keyword the next week??? I've been adding content and backlinks for my site. I mean, if I dropped from page 1 to page 2 that would be one thing... But, to go completely out of site???
Was it a new site? If so I'm afraid being no 1 was the anomaly, you've fallen back to your natural position. It's one of those strange phenomenon new sites often get an artificial push to the top, - I guess while the algorithm works out what they are - then fall to a more normal position.
Have you dropped completely out of Google's list? If so, is it a penalty for black hat seo - eg buying links??????
It is possible if you had duplicated content. That happens to one of my sites. I was unlucky just for 2 hours while updating my front page ... So now my site is back in google but my PR 3 is gone.
Nope, I haven't bought any links. Just commented on blogs and forums... I wrote the info on my site myself (just 2 blogs in the past week, just started it yesturday) and it's not copied... I email members sometimes but not often, could that be it?
What kind of keyword was it ranking for? If it was a completely new keyword and you were first to write about it, you could have been ranked well. Then as the biggies started writing on it as well, you drop out of the rankings.