Mine was one of the first sites hit on 2/24. I lost 40% of Google traffic. Panda took nearly all of the pages that ranked on page one for various phrases and moved them to page two to page five or twelve or worse.
It seemed at the time that the pages that were affected the least were those that had been the strongest pre-Panda for their phrases. For example, one page had been at the #2 spot for years for a particular phrase. That page got dropped to page two for the phrase, but later came back to #9 on page one.
Some pages still stayed in their #1 to #5 positions, but dropped in the last month or so to #8 or #9 or to page two or even to page three or four. These pages should have been the strongest of all, as they're completely original, focused and are the main purpose of my site. They're pages for individual retail stores in my niche, each with descriptions written by me or the store owners.
These would be found by searching for "(insert city or state name here) widget stores".
I'm thinking that I didn't have enough of these stores for particular states, and so all of the store ads for those particular states were hit. There's also the Google localization factor, as Google has its own results for searching for "(insert location here) widget stores".
It was definitely a sitewide demotion, as I have almost nothing left on page one.
Here's where Suggy's theory makes sense: my site had a low bounce rate. It had an average of four to five page views per visitor. Average time on site was one to two minutes. IOW, it kept at least certain visitors engaged.
If it meets the pattern that Suggy is suggesting Google is looking for, then that would make sense. Even though it was a popular site that kept most visitors, it met the "loser site' profile.