Chris Pirillo has a beef with social networks. It's called identity. A poseur on Pownce has snatched his identity, and started to sign up unwitting powncers as his friends. People he doesn't know. People who don't know him.
Virtually all social networks suffer from the same problem. As networks proliferate, individuals can't be members of all networks, and are therefore vulnerable to having their identity spoofed on that network.
The solution is OpenID. Claim your identity once, and assert it on every site that supports OpenID.
To make that work, of course, folks on Facebook, LinkedIn, Bebo, Pownce, Twitter, and so on would have to follow Plaxo's example, and support OpenID for login. Even better than what Plaxo does (support OpenID or their proprietary login) would be to simply support OpenID. Period.