Twitter is a social-networking service that allows you to post short updates of 153 characters or less to a bloglike webpage hosted on their site. The gimmick here is that once you've registered, you can set up your account to update your Twitter page via IM and cellphone text messages, as well as receive others' updates by the same methods. Maybe it's the forced brevity of the medium, but I find myself updating my Twitter account several times a day (and sometimes several times an hour), as contrary to my expectations the idea of people -- many of them complete strangers -- following my every waking thought and action is strangely much more fascinating than it is creepy.
Now if Twitter were GPS-enabled, that might veer a little into the Creep-O-Zone™. But as all of these Web 2.0 services converge how long will it be before our First Lives are identical to our Second? Google is thinking about moving into targeted advertising on electronic billboards, and by virtue of their wifi-enabled appliances and Bluetooth accessories most of the digerati are already walking mounds of metadata rich for the browsing. Who knows? Maybe in five years just by walking past me on the street you'll be able to pick up my RSS feed as I blog and Twitter my way through the Google-ified First/Second Life mashup that will be the future. I must admit the prospect is as scary to me as it is thrilling, but make no mistake: it's coming much sooner than we all think.