Hi. I'm working on a study guide about Google hacking, Shodan and direct network mapping. I need help understanding these concepts. Here are the questions.

1. Compare and contrast the difference between Google Hacking, Shodan, and directly network mapping system.

2. What are the differences in content provided from Google indexes versus Shodan?

3. Compare and contrast the passive (Google & Shodan) vs. active (network mapping & banner grabbing) approaches to intelligence gathering. 

4. What are the pros of passive (Google & Shodan) vs. active (network mapping & banner grabbing intelligence gathering?

5. What are the cons of (Google & Shodan) vs. active (network mapping & banner grabbing?