I think Google couldn't make up the system even more stupid that the current one with this Quality Score thing. I don't touch my ad or keywords and Quality Score sometime shows 9/10 and sometimes 2/10 for the same keyword and the same ad. Anyone else having the same problem?
I have had this problem before and was never able to find out what caused it. Of course, Google was no help when I asked them. These types of wild fluctuations tends to lessen ones faith in their system.