You have to be a tad bit self-centered and/or have nothing going for you in life to join Twitter. Since both apply to me, I've joined up as katerbee. If you too have a rotting soul and a mourning dove sent by Satan to wake you up 40 minutes before your alarm in the morning (assuming the upstairs neighbors' extremely loud and always-kept-on radio doesn't do it first), then you might be inclined to join Twitter and spend your day telling people in 140 characters or less "what is up" without them having to ask. Also, you can come up with irritating Twitphrases using all or part of the word "Twitter."
Hiked the top bit of Runyon today. Gorgeous view. You can see everything. Better than Mt. Hollywood (though not as hard). Didn't realize there were SO MANY HOUSES in the hills. Saw the hot reporter guy from Damages, which I am quite fond of. No shirt on (nice) and had a scary dog with him. Couldn't figure out where I knew him from--he was the guy who dumped Elle Woods in Legally Blonde. Personally, I would have preferred to see Tate Donovan. Boy, does that man improve with age.
Anyhow, Runyon's good. Next week I'll start having three day middle-of-the-week weekends which I plan to use to write like hell, read like hell, and hike my ass off. Well, not my ass. It's one of the few parts of my body that I approve of. Also, GRE studying. I think I'm finally giving in. Fall of 2010 will be my "you haven't broken into the industry at all, so you should really be doing something valuable with your time and energy." PhD will give me a break from my current loans, time to write, and summers off. I'm okay with that... if I have to be. :)
#3 of things that could go wrong: You could get a sunburn. On your scalp.