Although search engine optimization (SEO) only made up 11 percent of total search marketing in 2008, its numbers are expected to increase as internet users continue to find it more relevant than paid search.

That’s according to David Hallerman, a senior analyst at eMarketer, who predicts that the ratio of paid search to organic search will change in the coming years.

Last year $1.4 billion was spent on search engine optimization (SEO) while almost $12 billion went to paid placement, according to the Search Engine Marketing Professional Organization (SEMPO).

But Hallerman says that as internet users become less trusting of traditional advertising, search engine optimization (SEO) will see its stock rise.

"Internet users prefer organic listings to paid search. They generally find them more relevant – or simply more acceptable – than advertising," said Hallerman. "Therefore, they tend to click on organic results more often than on paid search ads."

He says that another reason for the expansion of search engine optimization is the cost-effectiveness of the technique and its long term results.

Earlier this month SEMPO predicted that search engine marketing (SEM) will reach $14.7 billion by the end of 2009. By 2013 that number is expected to rise to $26.1 billion.