I suppose the appropriate and slightly...okay...very flippant response would be that bloggers...well...blog.
Unfortunately, that answer doesn't fully answer the question.
Bloggers are indeed many different people doing and writing about many different things. With over three million active bloggers, there are really three million individual answers to that question.
Of course, that's a bit of a cop out too. By invoking everyone, the answer is no one. There has to be a better answer.
One thing all bloggers have in common is they write. Without writing, there is no blogging being created. Every post is written, with varying degrees of skill, by someone.
Writing is, however, only a tool. The purpose of writing, and of even the words themselves, is to communicate with others.
Bloggers wish to express their ideas, disseminate information, or even bare the deepest and most innermost aspects of their souls. There are blogs for all of these people.
Bloggers blog because they believe, in their hearts, that they have someting important to say to others. The blog provides the medium. The written words convey the message.
So after all of that, then, who and what are bloggers anyway?
Bloggers are believers in conveying thoughts and ideas in written form, to other people, on an individual basis.
It would be safe to say that bloggers are communicators of individual freedom of thought, speech, and the press. Along with that individual freedom is the right to agree or to disagree with others.
You might not always agree with the thoughts and ideas expressed by another blogger.
We should always, however, strive to defend their right to hold those views.
It's then your right, to use your freedom of expression, to change that blogger's opinions. Your blog is the vehicle to start that process of change.
Because of that exercise of their most basic freedom, bloggers are supporters of democracy in its purest sense.
It's therefore in everyone's best interest to defend the freedom to blog in their own individual way.
