Great thread, been following from start heres my story.
I started my first review site in Feb, by the beginning of June it was making around $150-$200 a week. I was really chuffed, then on the 24th June the dreaded message in my webmaster tools NOT the unatural links notice though this one said,
Dear site owner or webmaster of my site.com/,
We've detected that some of your site's pages may be using techniques that are outside
Google's Webmaster Guidelines.
Site totally de-indexed not just a penalty, so i assumed it was maybe to many key words in the reviews and articles, had been using the WP SEO Automation plugin h1,h2,h3, underling bolding and italics.
The site has a mixture of review posts and blog pages with articles. So i went in removed the plugin, removed all the h1,h2,h3 underling bolding and italics,reduced the keyword down on the page. Removed all the Amazon links just leaving 1 call to action button.
Sent in a reconsideration request,got the reply on Friday they still say the same,pages may be using techniques that are outside
Google's Webmaster Guidelines. What the hell! So now i'm in the proccess of re-writing all the reviews and post and will try again, don't want to give up on this site as it was a good earner.
Luckily at the begining of June i had started building 2 more review sites,they have made a couple of sales but it's early days for them hopefully in a couple of months they will be generating the same revenue as the de-indexed site.
For backlinking on the de-indexed site i was submitting articles to high PR web 2's and social bookmarking sites using many different anchor text linking to internal pages, then building link piramids to the web 2's using Wiki's article sites etc all with varied anchor text.
Just wish Google would actually say exactly what they don't like about the offending pages.