There are some good facts and numbers hidden in rather toy explanation: 1. Spam detection is automatic 2. There 6 types of spam -Unnatural outbound links (li

There are some good facts and numbers hidden in rather toy explanation: 1. Spam detection is automatic 2. There 6 types of spam -Unnatural outbound links (link selling) -Content copy/manufactering -Keyword stuffing -Forums/user generated spam -Parked domains -Sites hosted on spammy DNS -Different content humans and bots -Hacked sites 3. Google is removing as many as 50K spam sites per month, they get 8K reconsideration requests 4. Google's machine learned relevance model may be using about 200 features