Authority

1. Connections

1.1. Peers

1.2. Endorsements

2. Tone

2.1. Raving? Reasonable?

2.2. Self-aggrandizing

3. What do other people say about them?

4. Balance

5. Size of audience and following

6. Profile

6.1. experience

7. Credentials

7.1. Certifications

7.2. Resume

7.3. Accomplishments

7.4. Education

8. Gut

9. Quality of content

9.1. Professionalism

9.2. Validation