Over the past day or so, I have been seeing and watching a small increase in the number of threads discussing either global changes to the Google index or people complaining (at a higher rate) that their site is no longer ranking as well in Google.
Yes, Google is constantly changing, so this may just be that people are around more to notice? But the shift in the forum patterns that I watch on this specific topic is trending towards a possible Google update that is larger than a normal Google daily flux.
Again, this may be nothing or it may be early signs of an update coming. There have also been complaints both in the Google Webmaster Help forums and at WebmasterWorld of connectivity issues with Google.
The last time we reported on an update was in August where Matt Cutts of Google told us there was nothing going on.