So that’s what happens if your site gets blacklisted by Google!

Online metric firm Hitwise has published a case study of what happens to an otherwise successful website when it drops off Google.

According to Hitwise, an insurance comparison website called GoCompare.com was blacklisted by Google after the search engine allegedly picked up on irregular inbound links to its site, causing it to plummet down the rankings.

Before the ban, GoCompare had been the top website in Google’s organic results for the search term “car insurance”, capturing 17.49% of all clicks from the term.

But after Google took action on 26 January this year, GoCompare dropped down the organic rankings and suffered an 87% decrease in search traffic for the term, picking up just 2.31% of clicks from the term in the week following the blacklisting.

There were also consequences for GoCompare’s competitors – previous second and third ranking sites, Confused.com and Comparethemarket.com increased by 77% and close to 300% in the following two weeks.

“Search engines are the most important source of traffic to finance price comparison websites, accounting for over a third of their upstream traffic,” Hitwise analyst Robin Goad says. “Ensuring that a website is well-optimised for search engines is vital in such a competitive industry, but this example illustrates the fine balance that needs to be achieved between effective SEO and breaking the rules.”

It is also a clear illustration of the power of Google.