Twitter remains a popular social site for marketers as it currently has 241 million active users Twitter logomonthly. However, in its annual report, the firm acknowledges that ad rates have dropped for 7 quarters now. At the same time, the company’s user growth rate has been stalling and new research from eMarketer suggests that the user base is aging. These changes have implications for the firm and its marketers.

Analysts say that Twitter’s falling ad rates have been masked by the higher use on the platform. As more users click on ads, marketers have been paying for more ad but at lower prices. The firm notes that it has increased inventory and hopes that its lower rates will appeal to small businesses as it seeks to penetrate the local ad market.  While the company is competing hard for ad money and is courting marketers with its lower priced Promoted Products, some analysts believe the firm could find gold in its popular Interest Graph of Twitter that allows marketers to improve real-time messaging.

Of the firm’s 241 million active monthly users, about 43.2 million are U.S. consumers. eMarketer analysts believe Twitter will end this year with 48.2 million U.S. users which marks an 11.6% increase, a far lower rate than the 43% increase the social site gained in 2012.

Twitter currently reaches between 12.6% and 15.1% of the U.S. population, a sizeable target for marketers. What concerns some analysts is how the site’s users may age out. Twitter has historically had its highest penetration rates with 18-24 year-olds (37.4%) and 25-34 year-olds (26.1%).  Will these users continue to engage with Twitter as they grow older or will they move onto other platforms? The question is worth considering and marketers will surely be checking these numbers as they are often targeting audiences by age.

To learn more about Twitter users, check out the Audience Interests & Intent Report available at the Research Store on ad-ology.com.