Many webmasters believed that the 700,000 notifications Google sent out in the first two months of this year were related to link notifications. Not true, says Google’s head of search spam, Matt Cutts.
According to Cutts, 90% of the messages sent out via Google Webmaster Tools are related to black hat issues. Their estimates are that only 3% of the messages were about unnatural links on a page. You can find out more from Search Engine Land