I going to describe my own hypothesis called "Dilution of your likes":
The above two numbers mean, one user is doing 6 likes on an average. And that fellow is doing the samething everyday. He is of course going through more brands & websites. No. of likes in a year is 6365=2190. Your site has garnered 50000 likes so far. Lets assume all are from different users. And you had been in business for 2 yrs (I think you mentioned it above). Over NEXT (assuming the same stats for facebook and your like growth) two years, your existing 50000 unique fans have also liked 219050000=109,500,000 (100 mn likes). And you are expected to have another 50000 to 100,000 likes with a similar growth. A single like on your website is valued at 1 in 1 mn + (1 to 2 mn) = 2 to 3 mn. taking account of your new likes also.
Everybody is talking about the number of likes in their website and thats what facebook is showing. EdgeRank (IMHO) looks at the ratio between your likes and their all other likes - let me tell you why - in order to compare yourself to others and decide which post is relavent to him. And I am also making an educated guess that EdgeRank also looks at the timestamp of the like they gave you.
I liked you yesterday. Today I like Coke. That could be interpreted as Coke is my new Dangerousminds (to some degree atleast). And tomorrow Pepsi is my new Coke. Just speculating here... And I request someone who understands EdgeRank can correct my guess please. And your frequency of writing 12 posts a day could also be made known if I am facebook, I will see the latest like on your site and for 24 hrs / 12 = 2 hrs you are not updating your content and maybe facebook wants to take its users to new posts that they will like in those two hours. And Coke is not your competition because don't forget he has liked 1 mn other things which even if 1 % of them is creating a new post only once 1 day, your post is competing with 10,000 posts within those 2 hours. And Even if the user is refreshing for new posts every second of the two hours, 7200 times, you have more than 1 competition.
Every post on facebook must be given a number using some logic. You can compare only two numbers and decide. And EdgeRank assigns a number to all fed posts.
And they cant compare your post with all other posts to decide. One obvious way is to cluster the ones according to the user and decide as quickly as possible (within one sec max). How much computation can EdgeRank do for one user by the way? Cloud computing for 1 user? You might need the whole sky.
All are seeing the number of likes. Thats the numerator. But the total number of likes by the users in facebook is the denominator. And that is growing. Diluting the value of your post each time your own fan who liked you is liking something else.
Please comment. Thank you.