If you're not a geek - here's the bottom line of this post: 

The Facebook "like" buttons you see embedded on websites incorrectly report the number of "people" who "like" something.  Specifically, the button can inflate the displayed count of people.  While this is fine when all you want to do is track some general level of "engagement" with a particular item, it was not accurate for the use I needed - counting each "like" as a vote in our BoldBrush Online painting competition.  What I needed is a way to get the number of actual people who "like" something.  And there is a way to retreive that information from Facebook, but it is often a different number from what is shown on the "like" button itself. 

If you are a geek - here's the bottom line of this post:

If you're using the Facebook "Like" Button Social Plugin and you need an accurate count of the actual number of people who have clicked the "like" button, you can't rely on the number reported by the button itself.  You need to retrieve your URL's "fan count" number via Facebook's Open Graph API^[1]


Background

When I started our online painting contest, I had always planned to roll out a feature that allowed users to vote for their favorite paintings - eventually maybe creating some sort of people's choice award category.  When Facebook released the "Like" button social plugin, I thought it would be simpler to just use their code.  Plus, I thought, it would solve some problems.  I had always worried about implementing the feature myself because if awards were tied to the voting, there would be incentive to "game the system" and I just didn't want to deal with a bunch of fake user accounts and identity verification issues that would arise because of the gaming.  So I thought since most people use their real identities on Facebook, using the Facebook like button would largely solve the issue for me.

I recently added that feature to our online painting competition.  It lets Facebook users to "like" their favorite paintings.  After a few weeks, I thought it would be fun to use those "like" counts to rank the paintings in order of popularity, with the "most popular" being the ones with the most "likes."  So I dug into Facebook's api and found a way to retrieve the "like" data and hacked together a working solution.  So far so good.  The users were having a good time, it was interesting to watch the rankings change over time.  I also decided not to tie any awards to these rankings (at least for now) since I didn't know how accurate the "like" data actually was - I'm glad I didn't.


Like Button Inconsistencies

If you properly register your application with Facebook, the like button gives the application owner access to an administrative page for each item on his website that has been "liked."  I quickly started to notice something odd.  One of the early top-ranking paintings displayed 331 "likes" on the button itself.  This number matched what I was pulling from the api and was storing in my own database for ranking purposes.  But when I clicked through to the adminitrative page for that item, it clearly displayed "140 People like this."  There's a pretty big difference between 140 and 331 - way too big a difference if awards get involved.^[2]   At this point, I wasn't too worried since it was just for fun upon the initial launch, but with future uses in mind, I decided to dive-in and create a more controlled situation and see if I could figure out what was going on.


Duplicating the Problem

I visited a painting page that had no "likes" so far.  I also picked a time when contest activity was low (it tends to be frantic toward deadlines and slow right after one contest ends and the next one starts).  I also created a fake Facebook account (shhh don't tell Zuck) so that I could use my real account and the fake account to have data from two different Facebook users.

While logged into Facebook with the fake "B Rockhurst" account, I visited the web page and clicked "Like."  The next thing that happed was that the like button opened up a text box to allow me to type a message and "share" the item on my Facebook wall.  So I typed "cool" and hit submit.

Here's what the like button displays at this point:  "B Rockhurst and one other person like this"




So what's going on?  To find out, I called Facebook's handy api.  For this particular call I used the old REST api call in the following format:

http://api.facebook.com/restserver.php?method=links.getStats&urls=URL_OF_MY_WEBPAGE

Which returned the following XML:




Notice the "like_count" actually returns 1.  But and the "share_count" also returns 1.  That is correct.  "B Rockhurst" "liked" the page once and shared it once.  It seems, however, that the Facebook "Like" Button Social Plugin displays the "total_count" - which is now 2.  In fact, I was already aware of this issue and had been using the "total_count" for my painting rankings so that the numbers would match the reported Facebook like button counts.  I figured, in essence, everybody was allowed two votes - a "like" and a "share."  And had decided not to worry about it until I had more time to study it.


Next I logged into Facebook under my real account.  I visited "B Rockhurst's" profile and I clicked "like" under the shared item on his wall:



Then I called the API again, but alas, no change.  Apparently "liking" an item on another's wall doesn't inflate the count (somewhat ironically since this actually is an instance of another person "liking" the item).


OK, so what if I tried commenting?  So I commented on "B Rockhurst's" item by writing "pretty cool":




Again - checked the API - no change in the counts.

Hmmm. what if I shared the item directly from "Barrett's" wall?




Let's check the API again: