Everyone has heard stories about bloggers losing their full-time jobs over something they posted in their blog. Sometimes it happens to bloggers who are too personal or discuss their political or religious views that conflict with those of their employer. To top it off, many states have "at-will employment" laws stating that the employer can fire the employee at any time and for any reason. Likewise, the employee can quit at any time and for any reason.
According to http://www.dailyblogtips.com/ you can even get in trouble for what you write in comments on other blogs. It seems as though nothing is sacred.
Its a fine line. Yeah, you want to be able to say and write what you want, and we deserve some privacy, but the Web is a public place. When we write something, we're saying that we want whoever wants to to read it. That includes bosses, parents, and friends.
My advice would be to not use your real name while blogging or commenting if you have a full-time job other than blogging. And even if you do this, know that it is not all that difficult to find the person behind the screen name. So just blog as though everyone, including your boss and grandmother, might be reading it.