Well, it seems to be finally happening.  The Web 2.0 sites are starting to bubble up  -- no pun intended -- to the very top of the traffic charts, with MySpace and then YouTube eclipsing each other in weeks.  The Guardian reported yesterday that YouTube is now commanding 3.9% of all Internet traffic, making it the #1 site on the Internet. That's more than impressive given that they only started out in February, 2005.  I've been covering MySpace and YouTube in my last two pieces (one, two) because they in particular seem to represent leading edge best practices in the social architectures of large-scale public Web sites.  Ostensibly very "Web 2.0", both MySpace and YouTube aggressively "harness the collective intelligence" of their user's combined contributions as their primary offering to the world.  In this sense, they have put their architectures of participation at the core of their product design.  And wouldn't you know it, it's made them both leaders on the world stage.