Web 1.0 was all about creating long pages of content posted to a website and emails filling your inbox. But the only person interacting with your company was the person on the other side of those emails. Moreover, there really wasn't the chance for that person to "interact" with anyone - or perhaps more appropriately any thing - but your company.
Web 2.0 is really about giving users the ability to connect with one another - now that's interactivity! Which brings us to Metcalfes's Law. Applied here, it means the more users participating in more sites, the more dynamic the Internet will become.
In that light, to truly embrace Web 2.0 you need to start using your brand as a connection point between two or more parties, not just a connection point to your brand!