Expanding on an Agitator post of several weeks ago, here’s some fresh demographic data on social net usage from Harris Interactive.

5% of Americans online use Twitter, while 48% use Facebook or MySpace. No surprise … usage goes up with education, and down with age. For example, 74% of those ages 18-34 use Facebook or MySpace, while 24% of those 55+ do so. The corresponding figures for Twitter are 8% and 1%.

Meanwhile, in our very own Agitator spot poll (which you can still take here), 46% of respondents consider Twitter to be a "killer app" with great importance to nonprofits; 32% regard Twitter as marginally useful to nonprofits because of its demographic skew; and 21% regard Twitter as important as skywriting to nonprofits.

Have you voted yet?

Tom