MikeNoLastName - 3:01 am on Nov 8, 2012 (gmt 0)
I noticed the same effect that ichthyous indicated, in fact that is why I came in today, to see if anyone had an idea what might be going on. The WMT HTML improvements report showed significantly fewer duplicate titles and descriptions which we admittedly DO still have some of (archived 10+ year old weekly columns with the same column title and author), although the rest of the page is all different. Not sure if it is related but in the last few days the number went from around 250 on each report down to just under 50. Except we haven't done ANYTHING about them in the last couple months, and based on the list I printed out to work off of, there should still be around 235. Maybe they no longer consider these as a negative? I remember reading or listening to a very recent interview with Matt where he said something like: one shouldn't worry too much these days about duplication within the SAME site. Maybe they've just switched to ignoring them rather than penalizing?
I also noticed that a lot of these disappearing pages and those closely related are STILL ALL indexed and found by literal strings from them, but are now coming up on the Google PR tool as "Not Ranked" or 0's where they all used to be 1's. On the other hand, many of our other pages improved in the SERPS and the photos on these "duplicate-title" pages are as popular as ever in the image searches. We haven't made any significant changes to the site in months, except removing a single link to an offsite page from a navigation bar from about 50% of the pages.
Overall, between this heading into a annual normally slow period for us, the election yesterday, days of the week, etc. I just don't have enough steady data yet to tell if it was good or bad in total.