Anyone point in the direction on where to get some detailed information on Google's Quality score? I am trying to figure out what has gone wrong with my account after doing s well before.
Quality Score : This is the basis for measuring the quality of your keyword and determining your minimum bid. Quality Score is determined by your keyword's clickthrough rate (CTR), relevance of your ad text, historical keyword performance, the quality of your ad's landing page, and other relevancy factors. Quality Score matters: Ad Rank = CPC * Quality Score
a lot of people that don't know what is the Quality Score thing, imagine that it is a kind of Spirit that will make your AdWords+your business suddenly profit. please understand that I'm not telling that this is your case shirsc2 - you didn't provide further infor regarding what is wrong about your campaing (low traffic, bad conversion,...) Quality score is something that results with the improve of the volume of the traffic sent to your web site in a period of time - it do not has influence in the Quality of the traffic that is sent to your web site as his name suggests.
Google really doesn't disclose too much specific info about the quality score. Check this out for more info: Quality Score.