Internet does make the line beetwen privacy and public is no longer there.
Gee, maybe the line is bored enough, that's why he decided to disappear.
You want to find someone? just try to search their name first from search engine, couldn't find it? maybe you can search with their nickname.. Still couldn't find it?
Well, tell me their name, i want to congratulate them for being never been exsist in this virtual world (i refer to Internet world).
But, if you could find some link about the one that you search from the internet, well.. you can start "stalking" it.. Hmm, maybe looked at their profile info at Facebook. Or, suddenly found that they had a blog? Maybe you can get more info.. Find their Flickr? You might have a chance to see their picture, maybe alone.. with boy/girlfriend, friends, family time.. Got their Plurk or maybe their Twitter? More info you can get..
See.. Internet can change you to be a very good stalker. And after that, if all people do the same thing, where can you find that line between the privacy and public? Search engine sure make you are available to public.
But, of course there is some method to avoid it. Protect your update, change your privacy settings, and so on. But again, you'll be hard to find by you friends or colleague. And what's fun about that to be very secretive? LOL.
You the one who's can decide it.