Hover your pointer over the column headings to view a tool tip containing the definition of each metric in Social > Analytics > Posts.
Other Clicks = The total number of clicks not of the content of the post such as page title clicks, or clicks to "see more." (Total Count)
Other Clicks (Unique) = The number of people who clicked not on the content of the post such as page title clicks, or clicks to "see more." (Unique Users)
Link Clicks (ctx.ly) = The total number of clicks on a URL embedded in the Post (Reported by ctx.ly - Adobe Social's native URL shortener). It can differ from what social platforms report due to ctx.ly reporting all clicks on the URLs, not just clicks from the Post, and the ctx.ly numbers are updated in real time.