From The Scarlet Letter, Chapter 1, The Custom House (a chapter which is somewhat autobiographical):
The truth seems to be, however, that, when he casts his leaves forth upon the wind, the author addresses, not the many who will fling aside his volume, or never take it up, but the few who will understand him, better than most of his schoolmates or lifemates. Some authors, indeed, do far more than this, and indulge themselves in such confidential depths of revelation as could fittingly be addressed, only and exclusively, to the one heart and mind of perfect sympathy; as if the printed book, thrown at large on the wide world, were certain to find out the divided segment of the writer’s own nature, and complete his circle of existence by bringing him into communion with it. It is scarcely decorous, however, to speak all, even where we speak impersonally. But–as thoughts are frozen and utterance benumbed, unless the speaker stand in some true relation with his audience–it may be pardonable to imagine that a friend, a kind and apprehensive, though not the closest friend, is listening to our talk; and then, a native reserve being thawed by this genial consciousness, we may prate of the circumstances that lie around us, and even of ourself, but still keep the inmost Me behind its veil. To this extent and within these limits, an author, methinks, may be autobiographical, without violating either the reader’s rights or his own.
It seems to me that some bloggers have trouble with where to draw the lines in sharing personal thoughts and feelings in this “new medium” of internet blogging. However, is blogging so much different from publishing in print? Similar rules apply. Realize that anyone in the world might read what you have written, including the people you are writing about. Imagine your reader(s) as friendly souls, a sympathetic audience, but take care to preserve some “inmost Me behind its veil.” And respect the privacy of friends and relatives who might not like being the subject of your internet post–especially not the subject of criticism or true confessions. Speak the truth in love, and know when to quit blogging.