I live in the US, but in a non-typical place- Silicon Valley. So my reality here isn't the same as elsewhere in the US. But in the Bay Area, yes, blogging and micro-blogging sites are more popular than other parts of the US and the topics are more skewed to technology, startups, Internet. During election year in 2008, political thought dominated blogs around the country and the Red vs Blue ideology does dominate a lot of the regional blogs and ideology around the country.
Also, I think right now there has been a major shift where traditional journalists across the country who were noted columnists in traditional hard copy newspapers have started their own blogs and offer more frequent content and update than they did in the past, particularly since newspapers in the US have started to struggle for survival and some are only available online.
Otherwise, I think bloggers here are often folks who aspire to be thought leaders and also use blogging as one of their creative outlets.