Haochi has posted an interesting list of top users of popular social networking websites. He mentions very truly,
The Web, is not powered by any single individual, it is powered by us, the users
- YouTube: JamieKennedy
- Del.icio.us: thedysh
- Digg: 4bit
- StumbleUpon: flamewarrior
- Reddit: joel
- MySpace: oddballprotocol
- Facebook: dmb
- LinkedIn: Sorum
- 43 Things: Zeitgeist
This list is published according to Google result ranking and can change from time to time as well as from place to place.