Blogging is now common. Combining semi-blogs (like MSN Spaces, Fotolog and other similar crappy sites) with actual, real blogs (made and/or hosted via Wordpress, Blogger and communities like Kartones.Net), a lot of people now at least know what the term blog is.
From cooking recipes to song lyrics, from development to user experience and interaction, from music news to RPG play-sessions logs, internet is growing a lot with blogs.
Until last few years, companies have ignored (or just didn't know the existence of) blogs, with specific exceptions like game development companies (which are shifting from a general news website to development diaries of games). But as usually happens when something gets interest, all attention is drawn now to how cool is to have a blog, so companies need to be cool too and have blogs.
Corporate blogging ranges from a simple blog hosting, like MSDN does and every employee chooses if he wants one or not, to having multiple user blogs (for example a "Testing team blog"), or even directly providing all employees with a blog, whenever he uses it or not.
This would all be great, but the problem comes whenever a company wants to "look cooler" by having blogs with quality (or at least quantity) content. The easy way would be to have good motivated people (and they would write posts when they would feel inclined or inspired to do so), but the more frequent way is to force them.
And it can come in different ways; it might be insisting on having a post each x weeks posted, or "if you have a blog, cross-post here" (cross-posting is writing the same content for multiple blogs), or even forcing to have the corporate blog as the primary source.
If someone doesn't wants to maintain a corporate blog, the reactions come in different ways, usually being insisting via OutOfMemoryExceptions ("did I told you we're building corporate blogs? Would you like to participate? Oh, I already told you..."), via ArgumentNullExceptions ("Don't you really want to have a blog with us? C'mon, have a corporate blog, dude!"), via PolicyExceptions ("You MUST have a corporate blog if you own a personal development related one")...
The bad thing is that reactions go from nothing, to "thinking you don't care for the company" to more or less forcing you (I'm starting to look at it as another form of cloaked mobbing).
If at least it were during work time it would be ok (you do less actual coding to write blog posts), but usually is not, so remember: Your time, your knowledge, your ideas and your blog posts are yours.
If you choose to help having a corporate blog, do it your way: post some days after your original blog post, add a "Crossposted from xxx" footer, post only excerpts or resumes from your posts, or post different content (although if not done during work hours, I disagree with this option).