I just half-heartedly accepted an invitation to join FaceBook, but to be honest, I just don't have the time, energy or inclination to complete yet another profile. How exactly does it differ from Orkut or the more-useful-for-professional-networking LinkedIn? Can my old schoolfriends and colleagues not already contact me through Friends Reunited? You could literally spend all day keeping details updated on these myriad different (but ever-so-similar-really) sites.
If people want to keep up with my online adventures, then surely this blog, my del.icio.us bookmarks, Google Reader linkblog and Flickr photostream are sufficient? And if any of my actual friends do want to keep in touch, there's always MSN Messenger, Google Chat, Email, text message, phone calls, or even knocking on my front door and suggesting a pint at the pub. Step away from the keyboard, there's a real life out there just waiting to be lived!
Meanwhile, I am, however, very tentatively dabbling with Twitter, because I appreciate the brevity, ease of update (web, IM, text message, etc), and the way messages are instantly propogated to all your friends/followers. To some extent I'm still having difficulty grasping "the point" of it, but basically I understand it to be "what you do between blog posts", or when a whole blog post is overkill, or unfeasible (such as this entry from when I was sat in Pizza Express in Stratford on Avon last night). As always, time alone will tell whether I stick with it.