Five at Ten

Spend time with the family of Bill Gates, and eventually someone will mention the water incident.

The future software mogul was a headstrong 12-year-old and was having a particularly nasty argument with his mother at the dinner table. Fed up, his father threw a glass of cold water in the boy's face.

"Thanks for the shower," the young Mr. Gates snapped.

That aside, the "swine flu" Twitter-scare has once again proved the importance of context -- and how badly most Twitter conversations are hurt by the lack of it. The problem with Twitter is that there is very little context you can fit into 140 characters, even less so if all you are doing is watching a stream of messages that mention "swine flu."

This intractable contradiction has become a serious drag on the bottom lines of photo-sharing sites, social networks and video distributors like YouTube. It is also threatening the fervent idealism of Internet entrepreneurs, who hoped to unite the world in a single online village but are increasingly finding that the economics of that vision just do not work.

Last year, Veoh, a video-sharing site operated from San Diego, decided to block its service from users in Africa, Asia, Latin America and Eastern Europe, citing the dim prospects of making money and the high cost of delivering video there.