From the original article on SER: "As you know by now, Thursday/Friday of last week, we had two pretty important Google updates.
We had an EMD update on Friday and a Panda updatebegin on Thursday and continue throughout this week.
The question webmasters and SEOs are asking themselves, if they saw a drop in Google traffic, is... Was it the EMD update that hit me or the Panda update that hit me?
Clearly, if you have a keyword-less domain, for example, rustybrick.com, and if you were hit (was not), then you know it was Panda and not EMD.
But what if you are searchengineland.com and you were hit (was not), how do you know if it was EMD or Panda?"
Find out by reading the full article here: http://www.seroundtable.com/google-emd-panda-15792.html
Check also this forum discussion inside the Google Webmaster Help Forum: http://productforums.google.com/forum/#!category-topic/webmasters/y4VsfZ7fo_c