Fully one-half (52%) of B2B marketers say they are satisfied with their return on investment (ROI) in Twitter—and among those who attribute direct sales to Twitter, that satisfaction level is 66%, according to a survey from BtoB Online.

However, four out of five surveyed B2B marketers (80%) said they could not attribute direct sales revenue to Twitter marketing.

Among the 20% who could attribute revenue to Twitter, marketers were found to be more active on Twitter, committing more of their time to using it—to promote both their own content and the work of others.

To enthusiasts, Twitter is a powerful and relatively low-cost way reach a wide audience: One-half of B2B marketers said they tweet at least every other day—with those frequent Twitter users reporting higher overall satisfaction levels, more followers, and higher overall spending on social media programs.

Still, 70% of B2B marketers said they spend on average less than 30 minutes a day managing their Twitter stream.

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Few marketers have figured out how best to calculate Twitter's return: "Tracking ROI" was identified as the most challenging aspect of Twitter marketing.

On the other hand, in-depth interviews with B2B marketers revealed that many who describe themselves as satisfied with Twitter's overall value are not paying significant attention to measuring returns.

About the data: Findings are from the study Twitter in B2B Marketing by BtoB Online, which surveyed nearly 400 US B2B marketers, May 12-24, 2010.