Looks to me like a data push began on the 16th and is rolling through still. I'm seeing major changes on a couple of sites and have seen a few others mention it around the web. Looking at the datacenters shows differences of several hundred places in ranking in some cases.
Anyone else seeing anything?
I’m seeing movement too – one of my sites seems to be coming out of the sandbox 🙂 I saw the first hint about 10 days ago though.