It does depress me somewhat when I see people writing incredibly insightful or great blog posts on another company's blogging platform. I'd live in constant worry the company could fold up shop one day and your posts would be gone (unless you kept local copies manually).
It's your writing, if it is good and insightful, write it on a server you have control over.
I used to have a blog on my personal domain (not saying it was incredibly insightful), and I got tired of updating wordpress. One day the wordpress update failed, and I just took down the blog and now it is gone.
My livejournal blog however, which I set up over 10 years ago (and haven't updated in 7 years) is still there in it's embarassing completeness.
It's your writing, if it is good and insightful, write it on a server you have control over.