Last week, Ignite Social Media published a fat social network demographics report which covers more than 40 of the top sites (PDF). Ignite’s numbers were culled from search data, so they have to be taken with a grain of salt, but they do highlight some popular conceptions that might have to be reexamined, especially in regards to the idea of Twitter’s population being considerably older and more male than Facebook’s.

While Twitter is often seen as more male-dominated than Facebook, that’s actually not the case. Gender-wise both sites are about the same, though Twitter leads, with 60 percent users being female compared to Facebook’s 57 percent.

While Twitter is generally considered to be for an older demographic, that’s also not entirely the case. While 23 percent of Facebook’s users are under 25, compared to Twitter’s 18 percent, the largest number of Facebook users is actually older.

42 percent of Facebook users are over 45, while 37 percent of Twitter users are.

The most populous age group for Facebook users is also older: 27 percent are between the ages of 45 to 54, while Twitter’s most heavily populated age-group, on the other hand, is between the ages of 35 and 44.

Correspondingly, while both Twitter and Facebook users are about the same overall financially, there is a big difference being in households making less than $50,000 a year. While 28 percent of Facebook users earn below this mark, 36 percent of Twitter users do so. Facebook users are also more likely to have children than Twitter users, which further highlights Facebook’s older skew.

Though Twitter is still missing the youth presence, Ignite notes that there has been a significant increase in people under 17 doing searches for Twitter, so maybe it will one day capture this powerful market.

By Mark Alvarez