As customers ditch traditional customer service contact methods and flock to Twitter (News - Alert), only two companies – Zappos.com and LLBean.com – rank with a 100-percent response rate within 24 hours, according to a new study by STELLAService.

STELLAService obtained their stats using mystery shoppers online, all of whom tweeted basic customer service questions to respective official Twitter accounts. This occurred for a period of 45 days, every day, and mystery shoppers tracked not only the frequency of the response, but the speed by which each company responded.

It was LLBean.com and Zappos.com who replied to each and every tweet within a 24 hour time frame. STELLAService tracked 25 of the biggest online retailers.

STELLAService found that Overstock.com replied to 98 percent of all tweets within 24 hours, Dell.com came in at 98 percent, Best Buy at 89 percent.

"It’s becoming clear that social media savvy consumers are an incredibly important segment of any company’s customer base, both because they have higher service expectations and they have wide broadcast networks for sharing their experiences with others,” said STELLAService CEO Jordy Leiser. “By failing to take Twitter seriously as a customer service channel, companies may be inadvertently ignoring some of their best customers at their own peril.”

Leiser also said people who have used social media for customer service at least once in the last year are willing to spend 21 percent more with companies that provide great service, citing a recent American Express Global Customer Service Barometer.

Companies studied include Amazon.com Inc., Zappos.com Inc., Staples (News - Alert) Inc., Dell Inc., Office Depot Inc., Wal-Mart Stores Inc., Sears Holdings Corp., QVC Inc., Office Max Inc., Best Buy Co. Inc., Newegg Inc. and Sony Corp.

Apple (News - Alert) was excluded as the company apparently does not have a certified presence on Twitter.

The microblogging site has certainly helped many customers get much needed answers when all other methods failed. One user of the Firefox browser changed a setting that resulted in an undesirable result. A Firefox representative quickly provided a fix via Twitter and saved the day.

Michael Arrington (News - Alert) from TechCrunch shared his positive experience with Comcast (News - Alert) via Twitter, even back in 2008.

“And a piece of advice to anyone with a Comcast service problem:” he started. “Skip the hold time on their customer service line and go on the attack at Twitter instead. You may find your problem fixed in a hurry.”