Why Google Penalizing Sites
 

Google Penalizes Social Video Advertising Site Virool

why Google Penalizing and what happened to site which was penalized by Google

Google penalizes site because of following resons:
1. Excessive reciprocal links.
2. Duplicate content.
3. Overusing H1 tags.
4. Internal 404s.
5. Links from sites in another language.
6. Keyword stuffed content.
7. Hidden links.
etc etc...