I'm not sure why my main site was hit. It wasn't an EMD, no blackhat techniques, unique content, 100 + posts. It was an Amazon affiliate site, though. Maybe that has something to do with it. I also signed up to five web 2.0 sites and added 5 posts to each. But this was only yesterday, so I doubt that they've even been indexed yet. I pretty much did no backlinking, as the KWs were very low competition.
Anyone without an EMD experienced the same thing? What's your plan?