Google has announced a new feature to help fight against webspam, where sites cheat their way up search rankings.
Whilst English-language webspam in Google results was less than half what it was five years ago, there has been a slight increase in the past few months.
To counteract this, Google has introduced a redesigned document-level classifier, making it harder for so-called "webspam" content to rank highly.
"The new classifier is better at detecting spam on individual web pages, e.g, repeated spammy words - the sort of phrases you tend to see in junky, automated, self-promoting blog comments," said Google principal engineer Matt Cutts, in a blog.
"We've also radically improved our ability to detect hacked sites, which were a major source of spam in 2010. And we're evaluating multiple changes that should help drive spam levels even lower, including one change that primarily affects sites that copy others' content and sites with low levels of original content."
Google wanted to put to bed the idea the search giant did not take strong action against spammy content if those sites contained Google ads.
Cutts stressed adding Google ads to sites would not boost their search rankings and Google would take action on any site violating the company's quality guidelines.
"The fact is that we're not perfect, and combined with users' skyrocketing expectations of Google, these imperfections get magnified in perception," Cutts added.
"However, we can and should do better."
In another recent move to shore up security, the search firm bolstered its email authentication for Google Apps users.
