What Is The Difference Betwteen A 6-String & A 12-String

David Erickson of the Audiolicious.tv blog (Audiolicious.tv/) explains the differences between six- and twelve-string #guitars.
0:00 Intro
The most obvious difference is that a 12-string has double the number of strings a 6-string guitar has
0:30 How To Tune A 12-String
One of the main points of difference is how 12-string guitars are tuned.
2:08 Difference In Sound Between 6- and 12-String Guitars
12-string guitars are typically more difficult to play but he most important difference is the difference in how each sounds. You'll have to watch the video to hear that difference.