Why not? Everyone else is doing it and I already did anyway.
Back before everyone had the internet I let a friend publish some excerpts from my teen diaries in his magazine. So I obviously don't (didn't, at least) have a problem with putting it out there for all to see. However, my teen diaries were published 10 years after the fact. Live journaling or blogging are different. Immediate, irretractable, boring, charming, etc. If the internet had been available when I was 13 I would've been ALL over this live journaling. But now? At this age? hmmm. With the published teen diaries exception, I've only 'journaled' (is that even a word?) privately--many paged word docs stretching over several years. Yeah, if I had no sense of discretion, no self-censorship I'd just cut and paste the lot of it right on over here. But no.
I'll be back some night when I've got a good buzz on and start fresh.