Google, Bing and Yahoo apparently haven't convinced brands they need to build separate Web sites for access from mobile devices, because some marketers still think about repurposing desktop Web sites through a technique called responsive Web design. Responsive media, or Web design, means designing a Web site once, and formatting the content to accommodate access by multiple devices, from desktop to mobile. The technology isn't new, but the concept of using one set of code to do multiple tasks has grown. Through fluid grids, flexible layouts and media queries that allow designers to create specific layouts for devices, companies should be able to reformat desktop sites for access by mobile phone and tablet devices, according to Ethan Marcotte, a Boston-based Web designer and developer. Despite the fact that big companies pull their weight behind parts -- or all -- of the concept, not all search engine optimization (SEO) experts agree. The theory makes content available from one site to everyone who accesses the content from any device. But the interest driven by a low-cost implementation and maintenance fees has its shortcomings, according to Bryson Meunier, director of content solutions at Resolution Media. Some have called responsive design a solution to the problem of mobile SEO, although Meunier believes a mobile first solution is more competitive in organic search. Meunier said Marcotte never meant for responsive Web design to replace mobile sites. These sites should accommodate different goals from the user, and companies need to design Web sites that are specific to mobile. When it comes to search engine optimization, "if there's a lot of additional mark-up on the site that needs to be suppressed to deliver the content users want to see, it will slow down the site and possibly deliver the wrong content," he said. Providing a better mobile experience often requires specific mobile keyword research, Meunier said. State Farm Insurance and Esurance Car Insurance have content on their mobile sites that doesn't exist on their desktop sites. Having different content would not be possible with responsive Web design because the idea means using the same content formatted differently. Most people who search for information from these brands on a mobile device look for accident resources. "About 75% of mobile-query volumes related to these companies want towing services," he said, adding that the two companies highlight accident resources prominently on their mobile sites. Meunier is concerned that hundreds of companies are investing in a temporary solution that marketers believe is permanent. He also believes continued growth of responsive Web design could stall growth of the mobile Web if searchers aren’t finding what they need. "Link equity doen't enter into the equation similar to desktop search," he said. "In mobile search, Google, at least in December, had an update called old possum that allowed Webmasters to indicate with a redirect code the correct version of the page that should appear in mobile search results." The biggest problem with repurposing desktop sites into mobile is that search behavior on tablets and smartphones is different. Sites that are simply reformatted versions of the desktop are not likely to address all the needs of the mobile consumer.