Google has created algorithms that look for spam in websites that have been hacked.

In its announcement on the Google Webmaster Tools blog, the company said, “A huge amount of legitimate sites are hacked by spammers and used to engage in abusive behavior, such as malware download, promotion of traffic to low quality sites, porn, and marketing of counterfeit goods or illegal pharmaceutical drugs, etc.

“Website owners that don’t implement standard best practices for security can leave their websites vulnerable to being easily hacked. This can include government sites, universities, small business, company websites, restaurants, hobby organizations, conferences, etc.”

The problem for website owners is that hackers can gain access in a number of ways and the hacks can be hard to find. In some cases, your pages may show blocks of illegitimate text and links on some occasions and not others.

The more sites the spammers can hit, the more traffic they can generate for themselves. Google’s attempt to identify this type of spam is good, because it will then be able to automatically de-rank the sites that the spammers are promoting.

Google added, “We are aggressively targeting hacked spam in order to protect users and webmasters.

“The algorithmic changes will eventually impact roughly 5% of queries, depending on the language. As we roll out the new algorithms, users might notice that for certain queries, only the most relevant results are shown, reducing the number of results shown.”

Hacked spam removal from SERPs

As the graphic above shows, there will be fewer results as Google weeds out the offending websites and ignores pages of sites containing irrelevant spam.

For example, if your web pages are displaying paragraphs of text about cialis and leather handbags, and you didn’t put it there, Google could easily display that page for a search on those topics.

After Google’s algorithm is able to identify the text as spam, it would be able to remove your pages from the results.

How to tell if your website has been hacked

Here are a couple of tools you can use.