Google appears to be undergoing a major upheaval at the moment, our rankings have globally got better but some indivual terms have been up and down like a yo-yo. As of yesterday, things appear to have stabilised slightly but depending on what browser you use you can still get wideley varying results. Why Google have decided to do this just before their IPO I don't know, I do know that some companies are suffering hugely from this update and haven't got a clue when to optimise. Perhaps it's a new tactic where every search returns different results and hence optimising becomes very difficult (this would really mess up most automatic ranking programs, including Agent Web Ranking and the like). It would be a brave move by Google and would seriously upset many companies. Does it really matter if companies who optimise websites (including internal depts.) get hacked of with Google? I don't know, but there is a level at which resentment reach critical mass which influences public opinion. One major article in an important newspaper could cause a significant shift in market share (tipping points?).