Sites penalized for having same texts ?

[martincad]

This post is deleted!

[OlegKorneitchouk]

Is this possible that having similar content (90% the same in some pages) is something bad even when they target different countries ?

Yes, there was a Panda and EMD update around Sep 27 which could have affected your website traffic. Are they EMD? If not, it could be Panda - which focuses on low quality and duplicate content.

Does google send some kind of notification if your site gets penalized ?

No, unless there was a manual review of your website - in which case they would send you a notification via Google Webmaster Tools.

Re-written all the text, in order to show completely different texts, would it help getting back the organic traffic ?

Yup, that's how you recover from Panda (for the most part).