It looks like blogging could actually be good for you...
Self-medication may be the reason the blogosphere has taken off. Scientists (and writers) have long known about the therapeutic benefits of writing about personal experiences, thoughts and feelings. But besides serving as a stress-coping mechanism, expressive writing produces many physiological benefits. Research shows that it improves memory and sleep, boosts immune cell activity and reduces viral load in AIDS patients, and even speeds healing after surgery. A study in the February issue of the Oncologist reports that cancer patients who engaged in expressive writing just before treatment felt markedly better, mentally and physically, as compared with patients who did not.
I don't know about the physiological effects, but I can tell you that my spelling and writing has improved greatly since I started blogging years ago. Not enough for some of my readers, I'm sure, but for that reason alone it makes all the time I put into it seem more worthwhile.
So I guess we should consider blogging therapeutic. Of course, as is with everything else, moderation is the key.