Companies like Wal-Mart, Exxon Mobil and the makers of Motrin have all learned the hard way that online assaults from external users on Web 2.0 sites like Facebook and Twitter can damage their brands.

A survey by online researcher Hitwise found that such major companies should also move quickly to ensure that users seeking information about their brands online are really led to their sites by search engines. The results were released today.

Hitwise analyzed 30 leading e-commerce brands in the airline, appliance and electronics and insurance industries and found that when one in 10 US Internet searchers seek a specific brand, they are led away from the Web site of the brand owner, said Heather Hopkins, Hitwise senior online analyst in a blog post.

Overall, in the four weeks ending September 27, 2008, an average of 87 percent of searches for the top branded search terms like "Southwest Airlines" or "Best Buy" sent users to the brand owners' Web site.

At the high end, sent 96 percent of searchers typing "USAA" into the query box of a search engine were led to the Web site of insurer United Services Automobile Association, 94 percent of searches for United Healthcare were led to its site and Northwest Airlines was successful 92 percent of the time in directing searches to its site.

On the other hand, only 66 percent of users searching for a specific top appliance retailer, which Hitwise did not name, were led to the company's Web site, the research found. Hitwise also found only 75 percent of searches for one of the 10 largest airlines, also not identified, led to the company's Web site, while a top unnamed insurance provider's site was visited by 78 percent users trying to find it, Hitwise noted.

"This issue is huge for marketers," Hopkins noted. "When you search for a brand in the phone book, you don't find that brand's competitors listed. But when you search online, that brand's fiercest competitors often appear in the sponsored listings. Online businesses need to be aware of the extent of the problem and to understand the best ways to deal with threats."

While 90 percent of visits from searchers of "Southwest Airlines" went to the Southwest Airlines site only 66 percent of users searching for "Southwest Airlines reservations" made it to the airline's site. Some of the bad searches are caused by misspelled search queries, or when the query is combined with other search terms, Hopkins went on to note. For example while 96 percent of searches for "USAA" went to the USAA Web site, only 78 percent of "USAA insurance" queries were led to the site. About 12 percent of those queries were led to the USInsuranceOnline site, which includes links to multiple insurance brokers ready to provide price quotes to potential customers, Hitwise found.