Hi Guys, sorry to randomly jump in here but I wanted to share my findings regarding over-optimization.
For a while I have been using keyword | keyword | keyword format in my titles which historically has always worked. I manage around 25 websites and generally speaking Panda and Penguin haven't caused much of an impact. All sites have good unique content (although most are commercial). The interesting thing is that one site does appear to be hit so I de-overoptimized the on-page meta which has made no difference, whilst another site that was previously link 5 is now link 1 and in its current over-optimized state.
So I wonder whether the content is being weighed up against over-optimization. The difference between the 2 sites is that even though they are commercial, one is a buying site (de-overoptimized, suspicion of Penguin) and the other is informational (overoptimized, recently promoted).
This to me suggests some weighting in favour of what might appear to be a content based information site vs what is clearly a money site as the information site is unashamedly over-optimized and the other isn't.
As a side note, both sites are built by the same webdevs, sharing the CMS, server etc and are pretty much in the same way.