via youtube.com
The 12 Primary Social Media Interactions
The Vote

Use: A user is given the opportunity to show favor, or disfavor, for some content like a photo, video, blog post, etc. OR for a brand, group, individual, or idea.
Goals: Research, Awareness,
Examples: Facebook Like Button, Linkedin Like Button, YouTube Star Rating (before they were removed)
The Share

Use: A user is given the ability to share content with a friend, or group of friends.
Goals: Awareness
Examples: Share This Button, Post to Twitter Button