Social media site Twitter.com was shut down by a denial-of-service attack yesterday, leaving millions of users jonesing for contact with their Tweeps, or fellow Twitter users.

Other sites were also affected, The Associated Press reported, saying the attacks might relate to political strife between Russia and Georgia.

They started with hackers using a botnet to send a flurry of spam e-mail containing links to pages on Twitter, Facebook and other sites written by a single pro-Abkhazia activist, said Bill Woodcock, research director of the San Francisco-based, nonprofit Packet Clearing House, which tracks online traffic, AP reported.

Clicking on the links led to the activist's legitimate Web pages, but the volume of traffic overwhelmed the server.

According to comScore, Twitter had 20.1 million unique visitors in the United States in June, some 34 times the 593,000 a year earlier. That is only a U.S. usage figure—Twitter is used around the world.

Kailua-based Bare Feet Studios LLC partner and new-media guru Roxanne Darling equated the attack to “;when Wal-Mart's having a sale and everybody tries to get into the store at the same time.”;

Her partner, Shane Robinson, extended the analogy.

“;I would append that none of those people have actual intent to get into the store,”; he said. They rush the door en masse to keep everyone else out, “;and they are not there of their own free will; they are zombies.”;

The zombies are computers infected with malicious code instructing the machine, “;on this day at 12:01 a.m. GMT, or whatever, (to) ... start making their requests (to access) Twitter.com, Twitter.com, Twitter.com. Your machine is not going to ... give you any sort of notice that it is sending out these messages.”;

Twitter's and other companies' servers do something called “;load balancing,”; to send access requests to available servers, but when the servers are overburdened with requests, “;they can't load balance fast enough. And even if they could, the Web and database servers sitting behind them can't answer the requests for pages fast enough.”;

“;Even if 100,000 people managed to get into the store, there wouldn't be enough employees, shopping carts or space to handle the crowd, and everything would screech to a halt,”; Robinson said, resuming the analogy.

Companies' technology staffs can look for patterns in the sources of the requests and attempt to block them, but if not, “;you kind of have to ride it out.”;

Yesterday's outage caused “;very strong frustration”; not just for enthusiastic users, but for an increasing number of businesses grasping Twitter's power and potential as a marketing and customer-service channel, said Arleen Anderson, Internet marketing consultant.

In building the online presence of organizations, products and people, social media has become “;an important wheel on my wagon, (and) Twitter is a spoke in that wheel,”; Anderson's online business card says.

Businesses should not put all their social-media eggs into one basket, but should spread them around depending on whom they want to reach.

Some businesses use Twitter as a customer-relations management tool to further engage with their clientele, but “;the vast majority of Twitter users are newbies,”; who might not recognize Twitter outages, Anderson said.

Yesterday's outage may have left volumes of customer concerns flapping in the ether and companies' social-media managers unable to address them.

“;With an initial contact ... immediately get an alternative method of contact,”; such as a phone number, to ensure uninterrupted customer relations, she said.

Erika Engle is a reporter with the Star-Bulletin. Reach her by e-mail at .(JavaScript must be enabled to view this email address).