Steven Kamer's buddy list on Yahoo! Messenger represents much of his personal and professional universe: a gallery of user IDs networked to his life. When he gets to work every morning at Totality, a Web-services company based in San Francisco, the first thing he does is fire up his laptop and log on to this virtual world. His fiance is often waiting there, and so are his colleagues, who communicate mostly by instant messaging as they work to keep websites running smoothly for clients such as American Airlines and BestBuy.com
On a typical afternoon, Kamer, 30, participates in...