The ongoing WebmasterWorld thread has been pretty active with webmaster chatter since Sunday, when I went offline for two days.
It also appears that the automated tracking tools are seeing nice spikes over the past couple of days including Mozcast, SERPs.com and SERP Metrics. Although algoroo doesn't seem to agree.
About ten days ago we thought we saw a Panda refresh but Google would not confirm it.
Are you noticing fluctuations in your Google rankings and referrals?
Forum discussion at WebmasterWorld.