Dan Martin, VP of primary research for Nielsen Online, said Tuesday that the site's unique audience grew more than 100% in March, in part because of celebrity exposure, but just about 40% of Twitter's users return after one month of use. And that's up from previous months, Martin said.
The site has gained publicity recently following adoption by and widely disseminated comments from Oprah Winfrey, Ashton Kutcher, CNN, and Jon Stewart.
"Let there be no doubt: Twitter has grown exponentially in the past few months," Martin explained in a blog post on Nielsen Wire. "For most of the past 12 months, re-Oprah, Twitter has languished below 30 percent retention."
That indicates the site's growth will be limited, he said. Although high retention rates don't guarantee growth, retention is necessary for growth, Martin said.
"There simply aren't enough new users to make up for defecting ones after a certain point," he said.
Martin said Twitter still has time to correct the situation since it's a new site and some popular sites have overcome the same hurdle. However, the most popular social networking sites, Facebook and MySpace, have had much higher retention rates, he said.
"Twitter has enjoyed a nice ride over the last few months, but it will not be able to sustain its meteoric rise without establishing a higher level of user loyalty," Martin explained. "Frankly, if Oprah can't accomplish that, I'm not sure who can."
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