Hi Erwan,
Here is the message, what we got, Please have a look. Can any one please explain the seriousness or intensity of penalty?.
We’ve reviewed your site and we believe that some or all of your pages still violate our quality guidelines, which can be found here: http://www.google.com/support/webmasters/bin/answer.py?answer=35769#3. These guidelines outline illicit practices which may lead Google to take action on a site in order to keep webspam out of search results. In addition to this email, you may also receive a notification in Webmaster Tools regarding the outcome of your reconsideration request.
Specifically, look for possibly artificial or unnatural links pointing to your site that could be intended to manipulate PageRank. Examples of unnatural linking could include buying links to pass PageRank or participating in link schemes. Here is an article describing these techniques:
http://www.google.com/support/webmasters/bin/answer.py?answer=66356.
To illustrate how these articles could apply to you, here are examples of pages that contain inorganic links to your site:
{Online Free Coupons} -- http://www.allworldlinks.com/k/277/online-free-coupons.html
To find more links to your site, you can download a list in Webmaster Tools by doing the following:
1. Click on your site at https://www.google.com/webmasters/tools/
2. Click on 'Traffic' and then 'Links to Your Site.'
3. Under 'Who links the most,' click 'More.'
4. At the top of the page, click on 'Download more sample links.'
Please correct or remove all content that is outside our quality guidelines. You might consider reaching out to the webmasters of the sites with the inorganic links on them. For advice on how to go about contacting them, read http://support.google.com/websearch/bin/answer.py?answer=9109.
Once you have updated your site, reply to this email noting the specific changes you made. Only after there has been a significant decrease in unnatural linking will we consider reviewing your reconsideration request again. If there are still links that you could not remove, we will look for an explanation of why you were unable to do so.
If you’d like more specific advice for your site, consider posting in our Webmaster Help Forum, where a community of webmasters may be able to help you. You can post to the Forum by visiting the following link: http://groups.google.com/a/googleproductforums.com/forum/#!forum/webmasters.
Sincerely,
The Google Search Quality Team