Anyone wishing to write professionally [or do anything professionally, really] should read this article by John August. He reminds us all that our work on the internet can count for or against us, and explains the necessary components of professionalism in posting.
Not that anything committed to record has ever been really safe. The world reads Anne Frank's diary (remind me to burn my own before I die) and Jane Austen's letters to her sister.
On the worldwide web, however, we offer samples of our work for uncharted public scrutiny, items that say something about us and count toward whatever image the outside world has of us. Those samples might say things like "I couldn't pass a first-grade spelling test" or "No one ever taught me how and when to shut my mouth" or "Logic and I have never been properly introduced." They might also say "I have a keen creative streak" and "Kindness and reason are my best friends" and "My mother taught me how to present myself with common decency."
The thought scares me a little, but in a good way.