Austin, Portland, San Francisco and Seattle are the top local markets for people who read or contribute to blogs.

What they have in common are tech savvy and youth, according to (pdf) local-market research firm Scarborough Research, writes sister site MarketingCharts.

15 percent of adults in Austin are "bloggers" (readers or contributors), and are 78 percent more likely than the national average to be in this consumer group.

14 percent of Portland adults are bloggers, followed by San Francisco and Seattle, with 13 percent each, according to the data.

The national average for the number of consumers who read or write blogs is 8 percent, Scarborough said.

Among other findings of the study:

• 37 percent of Austin adults are between the ages of 18 and 34; they are 20 percent more likely than the national average to be within this age range.
• Austin adults are 17 percent more likely than adults nationally to be a part of a household that owns a DVR and 51 percent more likely to be a part of a household that owns a PDA.
• Adults in Portland are 13 percent more likely than the national average to be a part of a household that subscribes to satellite TV, and 18 percent more likely to be members of households that plan to subscribe to satellite TV within the next year.
• Bloggers are more than three times more likely than all internet users to download podcasts, and more than twice as likely to download/watch videos online: 25 percent of bloggers download or listen to audio clips online, compared with 8 percent of all other connected adults.
• Bloggers are also adopters of new technology: They are 76 percent more likely than all internet users to be a part of household that owns a PDA, 54 percent more likely to have an MP3 player, 37 percent more likely to have a satellite radio subscription.
• Demographically, bloggers are young and hail from middle-class families:
  • They are 66 percent more likely than the national average to be between the ages of 18 and 34.
  • 50 percent of bloggers are part of a household that has children under 17, compared with 41 percent of the total population.
  • Bloggers are 20 percent more likely than the national average to have an annual household income between $50,000 and $100,000 per year.

"Not surprisingly, the cities that rank highly for bloggers are also prominent internet-usage markets. Austin and San Francisco adults, for example, are more likely than the average to have a broadband connection at home," said Gary Meo, SVP, Scarborough print and digital media services.

"Additionally, Austin, Portland, San Francisco and Seattle are markets with large high-tech economies."

About the data: Source is Scarborough U.S.A+ 2007 Release 1 (current release). Based on total U.S. adults. DMA, or Designated Market Area, is a trademark of Nielsen Media Research.