Although social networks such as Facebook, MySpace and Twitter are increasingly popular, they have yet to live up to their promise as marketing vehicles. While 55 percent of 753 U.S. office workers in a recent poll are members of at least one of these social networks, 89 percent do not follow or are not friends with companies or brands. According to the survey, conducted by marketing firm, WorkPlace Media, 96 percent of respondents said a brand not having a presence on social networks makes no difference in their opinion of the brand. Also, 88 percent said their opinion of a brand doesn't change if there is a significant social network presence.

"It's clear that social networking is just that, it's social," said Terry Goins, WorkPlace Media EVP. The firm focuses on marketing services that reach consumers at their jobs. Goins said the survey shows that while the reach of social networks has grown, the impact on influencing consumers is not apparent. For example, in the findings, 75 percent of respondents have never recommended a product via a social network site, and 82 percent said they've never acted on a product recommendation from a social network site.

Of those who are registered on a social network site, 43 percent logged on to the site at work, and 78 percent spent less than 30 minutes on it. The most popular site was Facebook, with 89 percent of the social network participants in the poll having an account on that network, followed by MySpace with 40 percent, LinkedIn with 31, and Twitter with 18 percent.