Yes, Web 2.0 is a better information exchange, because it allows for more interactive communication between providers and participants. Newspapers, music labels, and radio involve one person producing content and another consuming it. With these methods, feedback is very slow. Modern communication with Web 2.0 is interactive, and allows for immediate feedback and reaction, which makes it better for communicating.
No, the Web 2.0 system is not less efficient than the older systems of information exchange because Web 2.0 can reach more people. In actuality, the web has less of a carbon footprint than newspapers do, because it does not produce waste. The web can reach people who want information when they want it. It is more efficient, not less.