Search engine optimization (SEO), once a niche product, has now become a must for businesses looking to compete in the 21st century and a new study finds it will continue to gain ground into the near future.

According to the "Search Marketing Trends: Back to Basics" report from eMarketer, $1.5 billion was spent on search engine optimization in 2008 – a number that is expected to increase to $3.8 billion by 2013.

eMarketer says the reason for the increase is the rise in consumers looking to the web for deals and discounts. This means there is less of an association with brand loyalty, with people preferring better prices.

The report also finds that while search engine marketing techniques like paid search gets the bulk of the attention, a number of marketers and businesses are turning to search engine optimization (SEO) as a cost-effective way to reach new customers.

According to the report, by 2013, more money will be spent on search engine optimization (SEO) than paid inclusion or contextual advertising.

Although the number of organizations using search engine optimization (SEO) is increasing, a recent report from practical ecommerce found that a large percentage of those implementing SEO do not understand the concept and do not see a problem engaging in what the industry might call unethical practices.