The like button aggregates more than unique likes. Indeed, the button count is the total of the following actions:
- The number of likes of this URL.
- The number of shares of this URL.
- The number of likes and comments on stories on Facebook about this URL.
In other words, if someone shares your URL on Facebook by copying and pasting it, it will be included in your likes count, even if they have not clicked on your like button.
Sharing the URL within a Facebook private message will also increase the like count (it was the case a few months ago. Current Facebook developers’ documentation doesn’t confirm this).
And if your visitor’s friends like or comment on your visitor’s share story, these actions will be added to the like counter.
Readers: Were you aware of what the figure next to like buttons represented?