Tim O'Reilly has posted a Web2MemeMap generated by the "What is Web 2.0?" brainstorming session. As you would expect, it is an interesting aggregation and extrapolation of ideas. The themes center around user participation and decentralization. There is not much on security (no Identity Metasystem?), per se, but all of the concepts have security implications (and sometimes conflicting goals and impacts), but right in the center of the map there is one security-centric issue:
"User Positioning: You control your own data"
This simple statement says a lot, it also gets right to heart of the Laws of Identity and specifically the First Law: User Control and Consent.