Not sure if it's Panda, but something slammed us this weekend. All keyword SERPS are down a page or so, with our main head term down from 45 to 114... but one of our related head terms is still #1.
We were hit with Panda in June, and between then and September, did a site refresh visually, and also reviewed, and removed large amounts of low quality content. Since about august we've been inching back up the SERPs by about a page or so a month. Until this weekend.
Something about it doesn't quite feel like Panda, esp. since our site is more panda friendly than it's ever been.
No penalties showing in WMT either.
And we've add about half a dozen legit .edu links in the last month...
If this is Panda we're seeing, then I'm at a loss.