You heard that right: If you think Twitter is for old people while Facebook is for the young’ns, think again.

A Pew report released last month — just noticed yesterday by the indispensable @NiemanLab — found the median age of a Twitter user to be 31, while the median age of a Facebook user is now 33. Back in May 2008, Facebook’s median age was 26.

Credit: Pew Research Center Publications

Since we are a youth organization that’s always thinking about the best ways to reach our demographic, this shift has big implications for Campus Progress. We use pages and, occasionally, ads to reach young people on Facebook. On Twitter, we’ve got an account as well as lists that categorize our members by the program and department they’re involved in.

Of course, we’ve all seen Twitter accounts belonging to users who signed up only to use the service infrequently or abandon it altogether. (Research indicates that a huge proportion of Twitter users are barely active.) When conducting its survey, Pew asked subjects if they ever use Twitter, but not how often they use it. The real question needs to be: What’s the median age of activeTwitter users compared to to active Facebook users.

I haven’t seen anyone try to quantify Facebook users’ level of activity — leave a comment if you know of such a study — but my totally un-scientific sense is that there tends to be less deviation among Facebook users: Almost everyone I know checks it at least once a day.

So maybe we shouldn’t jump to any conclusions just yet about which service is “better” for reaching young people. If age were all that mattered, MySpace, with a median user age of 26, would be the unquestionable choice for reaching our audience.

As my friend and former professor Eszter Hargittai has written, there are substantial differences in the way people use social networking not just based on their age, but also based on their socioeconomic status, ethnicity and religion. Campaigns and organizations like ours that want to attract a broad audience need to utilize a variety of outreach tactics and social media tools, not just one or two.

(Cross-posted at CampusProgress.org)