Now they able to identified bad content which is inserted on to hacked sites. As we already know,the number of sites attacked is staggering and the problem is only getting worse.They are too many hackers and spammers out there trying difference method to spammed any sites they thing can help in building backlink for seo.
Talk about hacked methods,below is an example:How Google informing the site owner about hidden text, a violation in Google webmaster guidelines.It's is good news you received such warning before your site is actually get banned.
In effort of counter this problem ,Google have launching the webmaster Message Center, it's a way for webmasters to receive "advice" or "personalized information" direct from Google.You can found it if you have register google webmaster tool.If Google found there is a problem occur on your sites(hack or been hacked) ,they will try to contact you, you'll see a notification in your Webmaster Tools dashboard.
Google will notify more webmasters of more potential issues we've detected on their websites, including:
* Spammy or abused user-generated content
* Abused forum pages or egregious amounts of comment spam
* Suspected hacking
These notifications are meant to alert webmasters of potential issues and provide next steps on how to get their sites fixed and back into Google's search results. If it pertains to a hacking or abuse issue, the notification will point to example URLs exhibiting this type of behavior. These notifications will run in parallel with our existing malware notifications.
In seo point of view,these kind of messages can be refer to search quality issues, according to Google, the Message Center also will act as a communication channel for more types of information between the webmaster and google.