A recent study by researches at Yahoo! found that while there are millions of users on Twitter and millions of tweets, about half of tweets received by users of the messaging service are written by only about 20,000 users.

The study breaks down the sources from which most Twitter users receive information, and what kind of information they receive. It has important implications for any nonprofit trying to spread its message via the service.

The study notes, for example, that “even though media outlets are by far the most active users on Twitter, only about 15% of tweets received by ordinary users are received directly from the media.”

Instead, users often receive their information through “intermediaries,” almost all of whom are not part of the 20,000 “elite” users. This presents an opportunity for an organization to build an audience while being an intermediary, perhaps spotlighting news relevant to its interests, and adding its own take as it passes information along.

Another finding of the study was that URLs shared by different types of “elite” users have different shelf lives. News-related links often had short lifespans, while links to blog content tended to resonate longer. That said, most long-lifespan URLs on Twitter were found to be links to media, such as videos or music.

This may indicate that nonprofits should promote their own blog entries and web-based analyses via Twitter, instead of simply relaying the latest news. It also indicates that advocacy campaigns which attempt to spread media (perhaps a YouTube video about your issue or campaign) may have better luck finding reverberations on Twitter.

The study’s findings are important for any group trying to spread its message on Twitter and attempting to find the best targets for its online outreach. Click here to read the full study and learn more about how messages spread on Twitter.