Google has introduced this change with the intention of targeting the sites that duplicate content from other sites and dont offer much useful content or information of their own. We highlighted this issue back in early January and just last week Google confirmed that they would be doing something about it soon.

This algorithm couldnt come at a better time; just recently Matt was forced to respond to criticism over Googles search result quality. He stated that Google would be 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. Seems that Google is certainly listening and has moved fast to quell any concern from users.

Matt has outlined more details on the update below:

This was a pretty targeted launch: slightly over 2% of queries change in some way, but less than half a percent of search results change enough that someone might really notice. The net effect is that searchers are more likely to see the sites that wrote the original content rather than a site that scraped or copied the original sites content.

Citing an example of website stackoverflow.com (who had complained of being outranked by content syndicators on Googles SERP), Cutts said that users will now see more of the original content from stackoverflow.com rather than those sites that were just reproducing stackoverflow.coms content.

The overall effect of the change is that web searchers are more likely to see in the SERPs, sites who have original content rather than sites that are just or copying and reproducing the original sites content.

Even though this announcement is great news for searchers, some complaints of sudden drop in traffic and change in rankings on the SERPs are already cropping up from webmasters. Hope Google has something up its sleeve to combat this