1: Where are you and what are you here for?

2: Who’s in the audience?

3: Do you dare mix business with pleasure?

4: It’s not just what you post

5: A picture is worth a thousand words — and can be a thousand times more embarrassing

6: Sensitive subjects can come back to bite you

7: Avoid the perils of PUI: Posting under the influence

8: Be ready to reject a friendship request or “unfriend” someone

9: Are you familiar with the site’s settings and options?

10: Should you use a pseudonym?

via techrepublic

Avoid These Social Networking Gaffes

• Choose Your Flavor
  
• Understand Site Culture and Rules
  
• Hone Your Profile
  
• Don't Be Pushy
  
• Do What You Say You Will
  
• Prepare for Face-to-Face Introductions
  
• Help Yourself by Helping Others

via monster