Google Webmasters said on Google+ that SEO spam is one of the primary reasons that websites are targeted by hackers. Some SEO spams redirect the users to malicious sites and this in turn causes the loss of customers.
Google wrote: “Search Engine Optimization 'SEO' spam is one of the primary reasons that vulnerable websites are targeted by hackers. Some forms of SEO spam can redirect your users to malicious sites and cause you to lose customers.
An early warning sign of this can be from customers trying to access your site. Be sure to pay attention to user feedback, questions, or complaints. Also, sign up for Search Console. If Google detects any malicious redirects, we'll send you a message in Search Console. #NoHacked”