Google have announced that hacked and spammed site represent a large chunk of thir manual penalty. As they implement the change they warn users that the overall impact is set to be 5% of queries (,depending on language) and that only the most relevant results are shown, reducing the number of results shown which is due to the large amount of websites being hacked spam.
If you want to check if your website has been hacked please read on the following steps:
- Check and scan your website with Google's safe browsing checker. It takes a few seconds and is free. Just type http://www.google.com/safebrowsing/diagnostic?site=yourdomain.com
- Open an account (if you haven't go one yet) with Google Webmaster. It provides tools, helps, tips, tutorials and any information of the overall health of your website. You will also find out if you have been penalised
- Perform a sucuri website malware and security scan. It is free and it scans for maware, if your website is blacklisted, injected SPAM and Defacements. https://sitecheck.sucuri.net//
- Another reliable and free website scan tool can be performed at https://safeweb.norton.com/
A google penalty can be truly devastating for your website and your business, and I speak from experience. So do not leave it to chance and perform some simple test to ensure you your site is safe and sound.