The blog Google Operating System has apparently discovered a new customization option that Google has been testing – called "preferred sites" – which could alter the way search engine optimization (SEO) is viewed.

The option will allow users to pick results that best fit what they are looking for – which could potentially assist the user in future searches.

"The preferred sites feature lets you set your Google Web Search preferences so that your search results match your unique tastes and needs," according to Google’s preferred sites help page. "Fill in the sites you rely on the most, and results from your preferred sites will show up more often when they’re relevant to your search query."

But some, like Josh Catone writing for Sitepoint says the new feature will "fundamentally" change search engine optimization (SEO) and could actually make it harder for users to find what they are looking for.

Many experts believe that 2009 will be the year Google begins to roll out its Universal Search which will likely attempt to personalize search in a way that has not been seen before.