robert76 - 1:18 pm on Jun 20, 2013 (gmt 0)
I came to Google in search of an answer to the same question and your post is only one that came up on the topic. I don't understand the terminology at all and Facebook seems to have obscured a real explanation. Like you, driving traffic to external URL but in my case clicks are almost double link clicks.
Have you figured out the terminology in the month+ since you wrote the post?