As the classic R&B song by the Persuaders goes, “It’s a thin line between love and hate.” The Annie Lennox remake of this is one of my favorites from her album Medusa. But, this post is not about my musical tastes. It is about the thin line that major brands are walking as they seek to deepen their interaction with consumers through social computing and other highly interactive Web 2.0 technologies. As anyone familiar with the song can tell you: the thin line is quite simply TRUST. Trust is created through personal investment, interaction and disclosure, the very things that these technologies enable. When trust is violated in a relationship, the deeper the relationship, the deeper the anger. So, the lesson of Facebook’s Beacon stumble is one that every Web 2.0 company should pay close attention to—the trust ante has been raised. Just as Web 1.0 privacy and trust issues sprung from Web 1.0 technologies, such as cookies and tracking a user’s Web surfing behavior, Web 2.0 issues will center on the much more delicate and private matters of personal profile information, social relationships and heretofore private interactions among friends, colleagues, acquaintances, customers and strangers. In Web 1.0, the solution was to never track a specific user’s identity for marketing purposes and to implement permission based marketing schemes. Mark Zuckerburg’s recent apology for making Beacon opt out by default, highlights the fact that in the frenzy of Web 2.0 even the basic Web 1.0 lessons have been forgotten. When in reality, we need stronger rules of the game to safeguard identity at the network and associated behavioral level.