Here's an interesting thing that's happened recently. I have maybe 20 websites with various emds targeting search phrases that are all pretty similar in nature targeting the same end sale product.
Here's what has happened lately: For an exact search (these are not my emds BTW--just an example) such as 'baby jogging stroller', my emd site for that phrase doesn't rank as well as another similar site I have titled BabyJogStroller dot com This has occurred on multiple versions of my sites so might be something to think about. Each site is structured similarly and has unique content so of course it could be the content causing this but I doubt it. Might want to diversify a bit and think outside the emd box.
I think Google for some silly reason thinks emds are more prone to being 'spammy' because until now it has given us schmoes a ranking advantage so this might be a way to somewhat curb this emd practice a bit. Just a guess but an educated one at that.
Just passing it along.