"About half [of the bloggers] are under the age of 30. About half use a pseudonym. About half say creative self-expression or documenting personal experiences is a major reason for blogging. About half think their audience is folks they already know. Half say changing people's minds is not a major reason behind their blog, and about half had never published before starting their blog."
Of course, since Pew slices the world into halves, EVERYONE fits into the profile (great way to be correct, when you think about it).
I know a handful of bloggers. Not a big sample, but I know these people personally, so I will be more bold than the tepid Pew position. While you can never really know what someone is thinking, I suspect that most of them are not out to change public opinion (in fact, it seems to me like most of them could care less about public opinion). Furthermore, I suspect that most post as a creative outlet first and to share and store useful information secondly. Most know (more or less) who their readers are. Most also post under pseudonyms, and are over 30 years old.
I think the most important tidbit from this article is that the blog super-stars do not fit the typical blogger mold. For the most part, the Big Deal bloggers are published people with an agenda. They fancy themselves to be opinion leaders and are using the internet to try and advance that vision.
I would hazard a guess that most blogger (the "silent majority") do not fit that model at all. So, when you see references in the media to bloggers, do not put us all in the same bucket, because I suspect we don't all fit the media's notion.