Although many newspapers have been quick to recognize the growing importance of social media, figures collected by Malcolm Coles suggest that social media do not reel in as many readers as newspapers would hope. In fact, Twitter brings in less than 1% of traffic to major UK newspapers websites like the Mail, Telegraph, and Guardian.
These figures are similar across the pond. Adam Sherk found that in the United States, Twitter also drives less than 1% of traffic to U.S. newspaper and magazine sites. However, Sherk does explain that this still makes it a top 25 referrer.

Both the Mail and Telegraph received 0.5% their referrer traffic from Twitter. As for the Guardian, about 0.4% of their visitors were led there by Twitter.

For the Wall Street Journal, social media represents a comparatively small source of traffic. However, social media does have the potential to drive readers who could eventually become subscribers, in the case of newspapers with paywalls.

Social media's importance can't be ignored - just last month, Facebook surpassed Google in number of visitors, but it seems that social networks do not represent important sources of traffic for newspapers. In fact, Facebook sends more users to news sites than Google News, but these are mostly broadcast news websites. Google News, currently mired in a battle over the right to use news content on its portal, sends most of its traffic to the New York Times and the Wall Street Journal.

If Twitter can't drive readers in large numbers, maybe the secret to unlocking Twitter's financial potential lies in advertisement on newspaper's feeds.

Sources: Coles, Sherk